A posse ad esse (ā poss´e ad ess´e).—From possibility to actuality.

A posteriori (ā pos-tē-ri-or´ī).—From the effect to the cause; that is, an argument by induction.

A priori (ā prī-or´ī).—From the cause to the effect; that is, an argument by deduction.

Aqua fortis (ak´wa for´tiss).—Strong water. A common name for nitric acid.

Aqua vitae (ak´wa vī´).—Water of life. Alcohol, brandy.

Arbiter elegantiarum (ar´bit-er ele-gan-shi-air´um).—An authority in matters of taste.

Arcana imperii (ar-kā´na im-per´ī-ī).—Secrets of the state.

Ardentia verba (ar-den´shi-a ver´ba).—Burning words.

Argumentum ad hominem (ar-gu-men´tum ad hom´-i-nem).—An argument to the man. An argument in refutation drawn from an opponent’s own principles.

Argumentum ad invidiam (ar-gu-men´tum ad in-vid´-i-am).—An argument appealing to low passions.