To fasten or secure something with a latch. She latched the gate to keep the dog from escaping.
To attach oneself to something or someone, often used metaphorically. The child latched onto her mother's leg, refusing to let go.
To become fastened or closed by means of a latch. The door won't latch unless you push it firmly.
Of a baby, to attach to a breast and begin suckling. The midwife helped the newborn latch quickly after birth.
To come to understand or realize something (usually followed by "on" or "onto"). After a few minutes, the students latched on to the concept.