A slit or narrow opening, especially one for receiving something, as a coin or paper. Also, a position or job in a group, series, sequence, etc.
A slot machine is a casino game that uses reels to display symbols and pay out credits based on combinations. Players insert cash or, in ticket-in, ticket-out machines, a paper ticket with a barcode into a slot on the machine. Then, they press a lever or button (either physical or on a touchscreen), which activates the reels to rearrange the symbols. When a winning combination appears, the machine awards credits based on the payout table. Most slot games have a theme and feature symbols and other icons that align with that theme.
In computer science, a slot is the operation issue and data path machinery surrounding a set of one or more execution units (also called functional units or FUs). A slot is usually part of a larger unit that defines a function, such as an assembler or compiler.
In football, a slot receiver is the third-string wide receiver who primarily plays on passing downs and catches passes thrown underneath coverage. These guys need to have a lot of speed and twitch to run routes like slants, switches, and crossers, which require them to juke the hell out of opposing linebackers. They are typically used to open up passes for the more skilled WRs on the team.