Dictionary.com
definitions

solidarize

[sol-i-duh-rahyz]
verb (used without object), sol·i·da·rized, sol·i·da·riz·ing.
  1. to unite or come together; become solidified.
Also especially British, sol·i·da·rise.

Origin of solidarize

From the French word solidariser, dating back to 1885–90. See solidary, -ize
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018