Definition from Wiktionary, the free dictionary
Alternative forms 
vest-pocket (not comparable)
- Small enough to be carried in a vest pocket or other small container.
- She carried a vest-pocket copy of the New Testament in her purse at all times.
- By extension, anything smaller than would ordinarily be expected.
- Levi's apartment was a vest-pocket Graceland; every inch of wall and shelf space was covered by Elvis memorabilia.