i Register
In some senses, flattop is marked as informal, US. Watch for register when choosing this word.
noun
A short haircut in which the hair is brushed straight up then cut flat across the top.
Well school's not so bad but the summer's better Gives me more time to see my girl Walk through the park beneath the shiny moon Oh when we kiss she makes my flat top curl
An aircraft carrier.
A type of stringed instrument, most often an acoustic guitar, with a flat top (as opposed to an archtop), with strings held in place with pins, and with a complex system of bracing struts on the top.
A grill with a flat cooking surface rather than metal bars.