High Quality Content by WIKIPEDIA articles! Tense–aspect–mood, commonly abbreviated tam and also called tense–modality–aspect or tma, is the grammatical system in a language that covers the expression of tense (location in time), aspect (fabric of time – a single block of time, continuous flow of time, or repetitive occurrence), and mood or modality (degree of necessity, obligation, probability, ability). In some cases, evidentiality (whether evidence exists for the statement, and if so what kind) may also be included.