Definition of strains:
(n) :
(biology) A particular variety of a microbe, virus, or other organism, usually a taxonomically infraspecific one.
(n) :
(figurative) Hereditary character, quality, tendency, or disposition.
(n) :
(music, poetry) Any sustained note or movement; a song; a distinct portion of an ode or other poem; also, the pervading note, or burden, of a song, poem, etc.
(n) :
Language that is eloquent, poetic, or otherwise heightened.
(v) :
(transitive) To apply a force or forces to by stretching out.
(v) :
(transitive) To damage by drawing, stretching, or the exertion of force.