1to add
2(math.) plus
3to increase; to augment
4(used before a disyllabic verb, often after an adverb like 不[bu4], 大[da4], 稍[shao1] etc, to indicate that the action applies to sth previously mentioned, as in 稍加改良[shao1 jia1 gai3 liang2] "make some minor improvements to (it)")