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.
busy chiefly stresses activity as opposed to idleness or leisure. industrious implies characteristic or habitual devotion to work. diligent suggests earnest application to some specific object or pursuit. assiduous stresses careful and unremitting application. sedulous implies painstaking and persevering application.