1. 给(婴儿)喂奶;哺乳
When a mother suckles her baby, she feeds it by letting it suck milk from her breast.

2. (婴儿)吃奶，吸奶
When a baby suckles, it sucks milk from its mother's breast.

1. give suck to

e.g. The wetnurse suckled the infant
You cannot nurse your baby in public in some places

Synonym: breastfeedsucknursewet-nurselactategive suck

2. suck milk from the mother's breasts

e.g. the infant was suckling happily