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, oration, book, etc.; theme; motive; manner; style; also, a
   course of action or conduct; as, he spoke in a noble strain; there was
   a strain of woe in his story; a strain of trickery appears in his
   career.