"highest point," Old English top "summit, crest, tuft," from Proto-Germanic *tuppaz (cf. Old Norse toppr "tuft of hair," Old Frisian top "tuft," Old Dutch topp, Dutch top, Old High German zopf "end, tip, tuft of hair," German Zopf "tuft of hair"); no certain connections outside Germanic except a few Romanic words probably borrowed from Germanic.
Few Indo-European languages have a word so generic, which can be used of the upper part or surface of just about anything. More typical is German, which has Spitze for sharp peaks (mountains), oberfläche for the upper surface of flat things (such as a table). Top dog first attested 1900; top-drawer (1920) is from British expression out of the top drawer "upper-class."
"toy that spins on a point," late Old English top, probably a special use of top (n.1), but the modern word is perhaps via Old French topet, which is from a Germanic source akin to the root of English top (n.1). As a type of seashell, first recorded 1680s.
"put a top on," 1580s, from top (n.1). The meaning "be higher or greater than" also is first recorded 1580s. Related: Topped; topping. To top off "finish" is colloquial from 1836;