減少
げんしょう · genshou · JLPT N3 · noun
decrease
📉 減少 = reduce + few: something cut down until there is little left
減 (gen) means to subtract or reduce, as in 減る, to decrease. 少 (shou) means few or little, as in 少し, a little. Put them together and you get a reduction down to less.
少 — 小 (small) + 丿 (slash stroke)
Originally a pictograph showing four small dots or grains, suggesting 'few' or 'small in quantity'. Over time it became distinguished from 小 (small) by adding a downward stroke. The core meaning shifted toward 'few' or 'little in number', while 小 kept the sense of physical smallness.