Old English þencan "conceive in the mind, think, consider, intend" (past tense þohte, p.p. geþoht), probably originally "cause to appear to oneself," from Proto-Germanic *thankjan (cf. Old Frisian thinka, Old Saxon thenkian, Old High German denchen, German denken, Old Norse þekkja, Gothic þagkjan); Old English þencan is the causative form of the distinct Old English verb þyncan "to seem or appear" (past tense þuhte, past participle geþuht), from Proto-Germanic *thunkjan (cf. German dünken, däuchte). Both are from PIE *tong- "to think, feel" which also is the root of thought and thank. The two meanings converged in Middle English and þyncan "to seem" was absorbed, except for archaic methinks "it seems to me." Jocular past participle thunk (not historical, but by analogy of drink, sink, etc.) is recorded from 1876.
Old English bettra, earlier betera, from Proto-Germanic *batizo-, from PIE *bhad- "good;" see best. Comparative adjective of good in the older Germanic languages (cf. Old Frisian betera, Old Saxon betiro, Old Norse betr, Danish bedre, Old High German bezziro, German besser, Gothic batiza). In English it superseded bet in the adverbial sense by 1600. Better half "wife" is first attested 1570s.
late 12c., "that which is better," from better (adj.). Specific meaning "one's superior" is from early 14c. To get the better of (someone) is from 1650s, from better in a sense of "superiority, mastery," which is recorded from mid-15c.
Old English *beterian "improve, amend, make better," from Proto-Germanic *batizojan (cf. Old Frisian beteria, Dutch beteren, Old Norse betra, Old High German baziron, German bessern), from *batiz- (see better (adj.)). Related: Bettered; bettering.
v. thought (thôt), think·ing, thinks
To exercise the power of reason, as by conceiving ideas, drawing inferences, and using judgment.
To weigh or consider an idea.
To bring a thought to mind by imagination or invention.
To recall a thought or an image to mind.