a container or receptacle from which a person at a party or the like draws a gift without knowing what it is.
any miscellaneous collection.
Origin of grab bag
An Americanism dating back to 1850–55
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for grab bag
a collection of miscellaneous things
US, Canadian and Australian a bag or other container from which gifts are drawn at random
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Idioms and Phrases with grab bag
A miscellaneous collection, as in The meeting amounted to a grab bag of petty complaints. This term alludes to a container offered at a party or fair, where one dips in for a party favor or prize without knowing what one will get. [Mid-1800s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.