AM and PM are associated with 12-hour timekeeping, as opposed to the international 24-hour clock. The 12-hour system grew up mainly in Northern Europe, and spread globally from there via the British Empire.
The adjective STRENUOUS has 2 senses: 1. characterized by or performed with much energy or force. 2. taxing to the utmost; testing powers of endurance. Familiarity information: STRENUOUS used as an adjective is rare.
1 marked by or uttered with forcefulness parents who voiced strenuous objections to the new textbooks Synonyms aggressive, assertive, dynamic, energetic, forceful, full-blooded, muscular, resounding, emphatic, vehement, vigorous, violentRelated Words decided, insistent, marked, pointed; absolute, categorical (also categoric), clear, plain, ...