Ft
WordNet
noun
(1) A linear unit of length equal to 12 inches or a third of a yard
"He is six feet tall"
WiktionaryText
Usage notes
As this abbreviation only eliminates the use of two characters, the full word, Fort, is generally preferred. It is also never appropriate to use this abbreviation in body text in any form. The same applies to Mt for Mount, So for South, and No for North. Use of Ft is only appropriate when space necessitates.