component

One coordinate of a vector. The vector `v = (3, 4)` has x-component `3` and y-component `4`. Decomposing a vector into components is just rewriting it as a sum of axis-aligned pieces: `v = 3·x̂ + 4·ŷ`. Components depend on the choice of axes — rotate the coordinate system and the components change, even though the underlying vector hasn't moved. Most calculations split a vector into components, do scalar arithmetic on each, then reassemble.