Definition of the word crunch up

The expression "crunch up" is a phrasal verb that combines the words "crunch" and "up" to describe the action of making something smaller and compact by folding or compressing it. In essence, the phrase "to crunch up" is a figurative extension of the literal meaning of "crunch" which refers to the sound and sensation of breaking or grinding something hard or crunchy such as an apple, leaf, or snow underfoot. The addition of "up" in this context perhaps connotes a sense of lifting or elevating the object being compressed, as if the user is squeezing or crushing it into a smaller form. The Oxford English Dictionary cites the earliest known written use of this phrasal verb as dating back to the year 1866, although the component words "crunch" and "up" have been separately in use since the 16th century.