Clave is the basic period, composed of two rhythmically opposed cells, one antecedent and the other consequent. Clave was initially written in two measures of (below). When clave is written in two measures, each cell or clave half is represented within a single measure. The antecedent half has three strokes and is referred to as the "three-side" of clave in the parlance of salsa. In Cuban popular music, the first three strokes of son clave are also known collectively as tresillo, a Spanish word meaning 'triplet' (three equal beats in the same time as two main beats). However, in the Cuban vernacular, the term refers to the figure shown below in the first measure. The consequent half (second measure) of clave has two strokes and is called the "two-side" by salsa musicians.