Abarim Publications' online Biblical Greek Dictionary
ει
The particle ει (ei) is a conditional conjunction and means if. It's pretty much on a par with our English word "if", and offers no major surprises. It is employed to introduce a situation or statement that is entirely hypothetical, typically without saying anything about the validity of the statement.
Our particle occurs 504 times in the New Testament, see full concordance, and also serves as element of a few compounds:
- Together with the curious particle αν (an), which expresses supposition or wish: the conjunction εαν (ean), meaning something like "if it would". This word occurs 343 times; see full concordance. From this word in turn comes:
- Together with the particle περ (per), which denotes entirety, the conditional εανπερ (eanper), meaning if truly or if wholly (Hebrews 3:6, 3:14 and 6:3 only).
- Together with the particle γε (ge), which puts an emphasis on what precedes it: the particle ειγε (eige), which means something like if indeed, if it were so. This curiously emphatic word is used 5 times; see full concordance.
- Again together with περ (per), which denotes entirety: the conditional ειπερ (eiper), which means "if indeed" or rather "since such and such is so" or "even if/even though". Depending on the context, this odd compound may imply that the supposition agrees with the fact (as is the fact, since such and such is true), or (when combined with an imperfect verbal tense), the opposite, namely that the supposition is contrary the fact (as if such and such were so, which it isn't). This compound is used 6 times; see full concordance.
- Together with τα (ta), the nominative and accusative plural of the definite article: the adverb of time and sequence ειτα (eita), meaning then, next, after, afterwards or after that. It's used 16 times, see full concordance, and from it derives:
- Together with the preposition επι (epi), meaning on or upon: the adverb επειτα (epeita), meaning thereupon, thereafter. This adverb is also used 16 times, see full concordance, and from it in turn comes:
- Together with the preposition μετα (meta), meaning in the middle or emphasizing transferal: the adverb μετεπειτα (metepeita), likewise meaning afterward, thereafter (Hebrews 12:17 only).
- Together with the preposition επι (epi), meaning on or upon: the adverb επειτα (epeita), meaning thereupon, thereafter. This adverb is also used 16 times, see full concordance, and from it in turn comes:
- Together with the conjunction τε (te), meaning "and": the conjunction ειτε (eite), meaning "and if" or "whether", which occurs 65 times; see full concordance.
- Together with the nominative single form of the relative pronoun, ος (hos), meaning "that/who/which": the adverb ωσπερει (hosperei), meaning wholly as if, just as it were. This useful concoction occurs in 1 Corinthians 15:8 only.