Why doesn't Answers recognize "gauge"?

Answers' spell-check told me that "gauge" (n-standard of measure, v- to measure) was not a word & offered "gage"(pledge/pawn) as an alternative. These words are not interchangeable. "Gage" has become a colloquialism for "gauge", presumably because of laziness & poor spelling. Dictionary.com lists them as interchangeable; my High school English teacher (1985) and my 1962 Merriam-Webster say otherwise. Any one else notice this??