The large four-part extensor muscle at the front of the thigh.(noun)
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 "quadriceps" in a sentence
"The quadriceps is the big muscle in the front of your thigh."
"The quadriceps is the big muscle in the front of your thigh that is responsible for lifting your body up and lowering it down."
"When you bend over at the waist, your psoas is disengaged and you have to lift the weight of your leg with your quadriceps, which is more work."