Ann Coulter, usually pretty good with her research, fails miserably at defining "semiautomatic," as in "semiautomatic firearm."
“Assault weapons” are defined as “whatever politicians say they are.” The guns that are banned and the ones that aren’t are functionally identical. They’re all semi-automatics.
Semi-automatics shoot one bullet per trigger pull — that’s the definition. Any handgun manufactured since the Civil War is a “semi-automatic.” The most basic self-defense revolver for women is a “semi-automatic.”
An example of a gun that is not a semi-automatic is a musket. Also those guns where a “BANG!” flag pops out when the clown pulls the trigger.
An automatic firearm — what militaries and drug cartels have — continuously fires when the trigger is pulled. They have been subject to a near-total federal ban in this country since the 1930s, so they’re irrelevant to the discussion.
Although revolvers do fire one shot per trigger pull, they are not semiautomatic because they don't use the force generated by the fired cartridge to cycle the action for the next shot.
Probably if you had to define a semiautomatic firearm, that would be a better fit: a firearm with but a single chamber, which uses the force of a fired round to cycle the action for the next shot. A semiautomatic firearm will fire one shot per trigger pull as long as cartridges are available to cycle the action.