A general idea or understanding of something: the concept of inertia; the concept of free will. See Synonyms at idea. 2. A plan or original idea: The original concept was for a building with 12 floors. 3. A unifying idea or theme, especially for a product or service: a new restaurant concept.
Upper lip twitching is caused by a sudden involuntary contraction of the muscle or muscle fibers in the lips or as a result of direct stimulation or injury, according to Health Hype. Lip twitches also result from tics, spasms and tremors. They are usually benign, but sometimes indicate an underlying condition.
Perfumes and lotions on human hands can cause horses to curl their upper lip. A stallion will make this face when he examines a mares urine to find out if she is in heat. The vomeronasal organ is orientated with the brain's sexual behavior center, and is used to decipher the pheromones a mare emits. Back to horse behaviors page.