intension

noun

1. intensity or the act of becoming intense.

   “Sounds […] likewise do rise and fall with the intension or remission of the wind.”

2. Any property or quality connoted by a word, phrase or other symbol, contrasted with actual instances in the real world to which the term applies.

   “'Is a plant', 'has a trunk', 'has leaves' are intensions of the concept tree. Its extension is the set of all trees existing in the real world.”

   “This law is, that the intension of our knowledge is in the inverse ratio of its extension.”

3. (dated)A straining, stretching, or bending; the state of being strained.

   “the intension of a musical string”