english
1
general::
Besides, in addition. For example, It rained every day and it was cold to boot, or He said they'd lower the price of the car by $1,000 and throw in air conditioning to boot. This expression has nothing to do with footwear. Boot here is an archaic noun meaning "advantage," and in the idiom has been broadened to include anything additional, good or bad. [c. A.D. 1000]
American Heritage Idioms
2
general::
Phrase(s): to boot in addition. • For graduation, I got a new suit and a coat to boot. • She got an fon her term paper and flunked the final to boot.
McGrawhill's American Idioms And Phrasal Verbs