Synonyms for Twig (same or very similar meaning)
WordNet sense 1 (a small branch or division of a branch (especially a terminal division); usually applied to branches of the current or preceding year):
sprig, branchletWordNet sense 2 (understand, usually after some initial difficulty):
tumble, catch on, get it, latch on, cotton on, get onto, get wiseFrom the ODE community, based on WordNetadd/edit