Dictionary.com
definitions

boldface

[bohld-feys]Printing.
noun
  1. type or print that has thick, heavy lines, used for emphasis, headings, etc.This is a sample of boldface
adjective
  1. typeset or printed in boldface.
verb (used with object), bold·faced, bold·fac·ing.
  1. to mark (copy) to be set in boldface.
Compare lightface.

Origin of boldface

First recorded in 1685–95; bold + face
Can be confusedbarefaced boldface bold-faced
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for bold face

bold face

noun
  1. printing a weight of type characterized by thick heavy lines, as the entry words in this dictionaryCompare light face
adjective boldface
  1. (of type) having this weight
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