Many people are comfortable using the word alumni to refer to someone who was a student of a particular school. However, others feel quite strongly that this is an error and that the following forms should be used: alumnus (for one male), alumni (for multiple males, or for a mix of males and females), alumna (for one female), and alumnae (for multiple females). The shortened form alum and its plural form alums began to be used in the 19th century. Initially, alum was widely viewed as highly colloquial or informal, but is increasing in use as a gender-neutral alternative.