Taka-sa

Taka-sa means 'height'; it is a noun derived from the adjective takai 'high, tall'.

Normally taka-sa is written 高さ, with the suffix -sa written in hiragana, as below:

Taka-sa seigen Height limit 2.1m

However, there is also a rather peculiar quasi-technical usage, found when writing dimensions, in which the suffix -sa is written in katakana (高サ). The sign below was right next to the sign found above.

Zujō chūi Taka-sa seigen 2.1m Attention overhead Height limit 2.1m

A Google search in August 2003 found that takasa was overwhelmingly written 高さ. Only in a small minority of cases was 高サ found.