verb

• (obsolete) To manage; to conduct; to treat.
  "But now, as our obdurate clergy have with violence demeaned the matter."
• (now rare) To conduct; to behave; to comport; followed by the reflexive pronoun.
  "they have demean'd themselves Like men born to renown by life or death."

noun

• (obsolete) Management; treatment.
  "Pursu'd him streight, in mynd to bene ywroken / Of all the vile demeane, and vsage bad"
• (obsolete) Behavior; conduct; bearing; demeanor.
  "‘When thou hast all this doen, then bring me newes / Of his demeane […].’"

verb

• (statistics, transitive) To subtract the mean from (a value, or every observation in a data set).
  "Concerning FE estimation, it makes no difference whether you demean the data with unit-specific means computed on (balanced) T observations per unit, or with unit-specific means computed on (unbalanced) Tᵢ observations per unit."