latch
Probably a 74HCT373 or 573? A latch is a digital storage element. While the latch enable (LE) is high on these parts, the outputs (Q) will follow the state of the inputs (D). The latches are said to be transparent in this mode. On the falling edge of LE, the state of the inputs is "latched" and the ouputs retain this state until LE goes high again.
A latch differs from a D-type flip-flop (or register) in that the flip-flop doesn't have a "follow" mode. A flip-flop's output only changes on a clock transition (there are both negative and positive edge-triggered flip-flops, just as some latches latch on the rising clock edge.).