Meaning
A globular structural protein that polymerizes in a helical fashion to form an actin filament (or microfilament).
Etymology
Origin: Ancient Greek
From Ancient Greek ἀκτίς (aktís, “ray”), based on the shape of the filament formed, + -in.
NYT Puzzle Appearances
No published puzzle dates on file for this word yet. It is part of the official NYT Spelling Bee word list for 2019, 2021, 2023, 2024, 2025, 2026.