BO (http://www.lojban.org/en/publications/reference_grammar/chapter5.html, http://www.lojban.org/en/publications/reference_grammar/chapter15.html, http://www.lojban.org/en/publications/reference_grammar/chapter18.html)

Joins tanru units, binding them together closely. Also used to bind logically or
non-logically connected phrases, sentences, etc. BO is always high precedence and
right-grouping.

ta cmalu nixli bo ckule That is-a-small type-of (girl type-of school). That is
a small school for girls.

