Wiktionary
vb. 1 To enclose with a fence. 2 (context idiomatic by extension English) To restrict freedom.
WordNet
Usage examples of "fence in".
He went back inside and suddenly the area of the fence in front of the door went off.
Spooky and Dixie made me wish I could've afforded to fence in my two acres.
Someone has dumped a length of barbed-wire fence in the ditch, and he has gotten tangled in the coils.
He had stared at her back, at her profile, at her pale, drawn features through that hole in the fence in Qyedlinhame often enough that he would know her anywhere and instantly.
A stocky swarthy-skinned man, presumably a foreman, in a shiny hard hat, noticed Rachael watching, and beckoned to her with a sly smile, but how could she have obeyed him even if she'd wished to, the six-foot chain-link fence in her way?