A Strain

1. The act of straining, or the state of being strained.
2. A violent effort; an excessive and hurtful exertion or tension, as of the muscles.
3. An injury resulting from violent effort; a sprain.
4. (uncountable, engineering) A dimensionless measure of object deformation either referring to engineering strain or true strain.
5. (obsolete) The track of a deer.