In reference to. See Usage Note at participle.(preposition)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "concerning" in a sentence
"Do you think he kept his word concerning his “threat”?"
"I'm curious about the title concerning Mar's magnetic field."
""So far," Sarela remarked, "you have kept your word concerning our well-being.""