pp1d07 necessarius (pleonastic)  NOT liber^necessarius NOT contingens^necessarius
Disambiguation In Ethica, necessarius is used in 3 senses, dealt with on 3 different notes pages:
1. necessarius(^liber) necessary, as opposed to free. Dealt with on notes page 1d07 liber^necessarius
2. necessarius (^contingens) necessary, as opposed to contingent. Dealt with on notes page 4d03 contingens^necessarius
3. necessarius (pleonastic) necessary where used pleonastic. Dealt with on this notes page.
Note: Nowhere in
Ethica "necessary" is used in the (non-causal) sense of modern logic and mathematics, where the following 4 expressions are equivalent: 1. B is necessary for A 2. if not-B then not-A 3. if A then B 4. A is sufficient for B.
Meaning Stressing the positive, geometrical, certain, proven status of a sentence or sub-sentence
Mantras [what is] "...essentia involvit necessario existentiam..." (= [mng eqv] "...essentia involvit existentiam...")
"ex necessitate divinae naturae" (= [mng eqv] "ex divina natura" )
"est necessario in Deo adaequata" (= [mng eqv] "est in Deo adaequata")
Related concepts vere where not linked to pp1a06 veritas and absolute where not linked to 1d02_in suo genere^absoluta finita^infinita (see there under NOT linked)
Occurrence [geomap]
NOT linked: necessarius where used in oppostion to liber, linked to 1d07 liber^necessarius.html
necessarius
where used in opposition to contingens, linked to 4d03 contingens^necessarius
N.B. "necessario est": is NOT pleonastic when "esse" is used in the sense of pp1d03 esse, dari, that is, explicitly referring to the status of existence. Necessario then means "its essence involves it", which is not by definition the case for every existing thing. In such contexts "necessarius" has the sense "necessarius (^contingens)". Similarly in "debet necessario existere", necessario can NOT safely be taken always to be redundant. cf. {2p13} demonstratio: "deberet (per propositionem 12 hujus {2p12}) necessario alicujus ejus effectus idea in mente nostra dari.
N.B. "necessario vera" is NOT pleonastic: an imagined idea may be true by accident but never is necessarily true. Necessarily true are only the adequate ideas, hence the local meaning is: necessarius (^contingens).

More pleonastic use of "necessarius"
"...
necessario sequi" (passim, first in {1d08}), English: "necessarily follow"... There is no complement "unnecessarily follow". "Necessario" is redundant, an expletive expressing certainty, sure(ly), can't possibly be otherwise, following from its essence, proven, definitely.  {1p07} and passim: "necessario involvit = involvit", "debet necessario" = "debet", {5p06} "ut necessarias intelligere" ("understand as necessary") = "intelligere" ("understand"), "necessario sequi" = "sequi", "ergo necessario" = "ergo", "concludere modo necessitate" = "concludere",  "necessario determinari debuit" = "determinata est" (triple pleonasm), {1p34} "ex sola...necessitate Dei essenti"  (from the sole necessity of the essence of God) = "from the sole essence of God". "ex necessitate naturae" = "ex natura" Most of these expressions occur in both equivalents.

{1d07 liber^necessarius}                                                              ... the term defined in this definition is necessarius (^liber), however in its first  occurrence, necessitas has the sense necessarius(pleonastic) : ex sola suae naturae necessitate existit ex sola suae naturae existit ...
...That thing is called free, which exists solely by the necessity of its own nature, and of which the action is determined by itself alone. On the other hand, that thing is necessary, or rather constrained, which is determined by something external to itself to a fixed and definite method of existence or action. ...Ea res libera dicitur quae ex sola suae naturae necessitate existit et a se sola ad agendum determinatur. Necessaria autem vel potius coacta quae ab alio determinatur ad existendum et operandum certa ac determinata ratione.
{4d03 contingens^necessario}                                                      ... the meaning of necessario used in this very definition of contingens(^necessarius) is NOT necessarius(^contingens) but necessarius (pleonastic)  : necessario ponat = ponat, necessario secludat = secludat...
III. Particular things I call contingent in so far as, while regarding their essence only, we find nothing therein, which necessarily asserts their existence or excludes it. III. Res singulares voco contingentes quatenus dum ad earum solam essentiam attendimus, nihil invenimus quod earum existentiam necessario ponat vel [excl non-exh] quod ipsam necessario secludat. 
Spinoza's awareness where "necessario" is redundant
"Necessario(pleonastic)", when occurring in a proposition, is sometimes NOT copied to its QED-repeat routine at the end of a demonstration, showing Spinozas awareness that necessario is redundant: {1p08} "PROPOSITIO: ...est necessario infinita" "DEMONSTRATIO: ...Existit ergo infinita. Q.E.D.". The inverse also occurs: "Necessario" being omitted in proof-string but added in the routine QED repeat routine:  {5p33} "PROPOSITIO: ...est aeternus. DEMONSTRATIO: .......est etiam necessario aeternus. Q.E.D."
Elwes sometimes, for instance in {1p33}, handles redundancy by simply ignoring necessitas:  for "ex necessitate naturae Dei determinatae sunt" he renders: "by the nature of God are conditioned to exist". There are two redundant "necessario"s in the Latin of {2d02}, Elwes ignores one, leaves the other which Spinoza could have skipped as well: "...essence of a thing [is] that, which being given, the thing is necessarily given also" (= the thing is given also).
Equivalence claims involving necessarius (pleonastic)
{1d07} [notes] 1. free 2. that thing which exists solely by the necessity of its own nature, and of which the action is determined by itself alone. 1. libera 2. Ea res  quae ex sola suae naturae necessitate existit et a se sola ad agendum determinatur.
{1p07} 1. be its own cause 2. its essence necessarily involves existence 3. existence belongs to its nature. 1. est causa sui 2. ipsius essentia involvit necessario existentiam 3. ad ejus naturam pertinet existere.
{1p17} 1. solely from the necessity of the divine nature 2. solely from the laws of his nature,  1. Ex sola divinae naturae necessitate 2. ex solis ejusdem naturae legibus
{2d02} [notes] 1. the essence of a thing  2. that, which being given, the thing is necessarily given also, and, which being removed, the thing is necessarily removed 3. that without which the thing, and which itself without the thing, can neither be nor be conceived. 1. essentiam alicujus rei 2. quo dato res necessario ponitur et quo sublato res necessario tollitur 3. id sine quo res et vice versa id quod sine re nec esse nec concipi potest.
{4d03} [notes] 1. contingent particular things 2. [particular things] which, while regarding their essence only, we find nothing therein, which necessarily asserts their existence or excludes it. 1. [Res singulares] contingentes 2. [Res singulares] quatenus dum ad earum solam essentiam attendimus, nihil invenimus quod earum existentiam necessario ponat vel [excl non-exh] quod ipsam necessario secludat.