Shirabe
Common Noun family or surname given name or forename, gender not specified
English jmdict
1
noun (common) (futsuumeishi) triangle;triangular shape
English jmnedict
1
Sankaku
English jmdict
1
noun (common) (futsuumeishi) mathematics trigonometric function
I think that for many people learning the trigonometric functions is meaningless.
Other forms