Beian

Etymology
From the Hanyu Pinyin romanization of, without syllable-dividing mark.

Usage notes
can be considered a misspelling of. In theory, a syllable-dividing mark should be added before a non-initial syllable beginning with, , or. Hence, is not allowed since a word made up of  and  would be spelled as  (cf. Bei'an). In practice, syllable-dividing marks are often added or omitted at will.