An adverb from heteros (G2087, other, different). Heterōs means in a different manner, otherwise, differently. Rare in the NT (appearing in Philippians 3:15), but its root heteros is theologically significant in distinguishing one kind of thing from another.
The word heterōs appears only once in the NT — Philippians 3:15 — where Paul writes: 'And if on some point you think differently (heterōs), that too God will make clear to you.' This is a remarkable statement of pastoral grace combined with confidence in divine instruction. Paul does not demand immediate uniformity of theological opinion; he trusts the Spirit's ongoing work to bring alignment. The root heteros runs through important Pauline distinctions: heterodidaskalein (1 Tim. 1:3 — to teach a different, false doctrine), heteros euangelion (Gal. 1:6 — a 'different gospel' which is no gospel at all). The distinction between allos (another of the same kind) and heteros (another of a different kind) matters theologically: there is no other kind of gospel, no heterodox addition to Christ.