From BiblePortal Wikipedia

Vine's Expository Dictionary of NT Words [1]

1: Ὄψιμος (Strong'S #3797 — Adjective — opsimos — op'-sim-os )

akin to opse and opsios (see LATE), denotes "late," or "latter," and is used of "the latter rain" in  James 5:7 (the most authentic mss. omit huetos, "rain;" some have karpos, "fruit"); this rain falls in March and April, just before the harvest, in contrast to the early rain, in October. In the Sept.,   Deuteronomy 11:14;  Proverbs 16:15;  Jeremiah 5:24;  Hosea 6:3;  Joel 2:23;  Zechariah 10:1 .

 1—Timothy 4:1Later 2—Peter 2:20Last.

Webster's Dictionary [2]

(1): ( a.) Of two things, the one mentioned second.

(2): ( a.) Recent; modern.

(3): ( a.) Last; latest; final.

(4): ( a.) Later; more recent; coming or happening after something else; - opposed to former; as, the former and latter rain.

King James Dictionary [3]

LAT'TER, a. an irregular comparative of late.

1. Coming or happening after something else opposed to former as the former and latter rain former or latter harvest. 2. Mentioned the last of two.

The difference between reason and revelation - and in what sense the latter is superior.

3. Modern lately done or past as in these latter ages.