(simile) Very tough (very strong)

plural of steel-toe boot

(biology) A phenomenon concerning the suppression or prolongation of estrous cycles of mature female mice (and other rodents), when females are housed in groups and isolated from males.

singular of seven-league boots

plural of cold boot attack

(cryptography) A type of sidechannel attack in which somebody with physical access to a computer is able to retrieve encryption keys from a running operating system after a reboot. It relies on the fact that the contents of memory can still be read for a short period after power is cut off.

(informal) To try hard to please someone.

(figuratively) Practical experience.

Alternative form of quake in one's boots

(informal, sports) To retire from or stop playing a field sport.