Early - Vine's Expository Dictionary of New Testament Words
Early
[ A-1,Noun,G3722, othros ]denotes daybreak, dawn" (cp. Lat. orior, "to rise"). Used with the adverb batheos, "deeply," in Luke 24:1, it means "at early dawn" (RV). In John 8:2 it is used in the genitive case, orthrou, "at dawn," i.e., "early in the morning." In Acts 5:21, it is used with the article and preceded by the preposition hupo, "under, or about," lit., "about the dawn," "about daybreak," RV (for AV, "early in the morning.").
[ B-1,Adjective,G3720, orthrinos ]
"early," akin to A., is a later form of orthrios. It is found, in the most authentic mss., in Luke 24:22, of the women at the sepulchre, lit., "early ones" (some texts have the form orthrios, "at daybreak").
[ B-2,Adjective,G4406, proimos ]
or proimos, a longer and later form of prois, pertaining to the "morning," is formed from pro, "before" (cp. protos, "first"), and used in James 5:7, of the early rain.
[ C-1,Adverb,G4404, proi ]
"early in the day, at morn," is derived from pro, "before" (See B, No. 2, above). In Mark 16:2, AV, it is translated "early in the morning;" in Mark 16:9; John 18:28; John 20:1, "early;" in Matthew 16:3; Matthew 20:1; Matthew 21:18; Mark 1:35; Mark 11:20; Mark 13:35; Mark 15:1, "in the morning;" in Acts 28:23, "(from) morning." See MORNING.
Note: In Matthew 20:1, hama, "at once," is redered "early."