εἷς

Adjective: εἱς (heis), GK G1651 (S G1520, G3391), 343x. εἱς is the cardinal number “one.” It can be used simply to count items, like one talent (Mt. 25:15). εἱς is occasionally also used like an ordinal number, as in “the first woe” (Rev. 9:12) and the common NT phrase “on the first day of the week” (Lk. 24:1; Jn. 20:1; Acts 20:7; 1 Cor. 16:2). Many of the NT uses of εἱς refer to the singularity of God—“one God” (Rom. 3:30; 1 Cor. 8:4, 6; Gal. 3:20; Eph. 4:6; 1 Tim. 2:5). εἱς can be used less like a numerical indicator and more like an indefinite pronoun or indefinite article. For example, Matthew uses εἱς to describe “a [certain] scribe” (Mt. 8:19) and “a man” (19:16 [NIV]).