top out
Etymology
Old EnglishEnglishAmerican English
Combines 'top' (from Old English 'topp', meaning highest point) with 'out' (emphasising reaching the end or limit). The phrasal verb emerged in American English in the mid-20th century, likely from building construction (to 'top out' a building = to complete the highest structure) and later extended to prices, speeds, and other measurable quantities.