28th

28th is the ordinal form of the number 28, used to indicate position in a sequence. In English, ordinal numbers are generally formed by adding a suffix to the cardinal number; most numbers take -th, while 1, 2, and 3 take -st, -nd, and -rd respectively. Therefore, the number 28 becomes 28th.

The term is commonly used in dates and calendars. The 28th day of a month refers to the day that falls on the 28th, as in the 28th of January. In leap years, February has 29 days, so February 28th is the day before the extra day.

Geographically, 28th can designate a latitude line: the 28th parallel north is an imaginary circle around the Earth approximately 28 degrees north of the equator. It passes through several countries and has appeared in historical and geopolitical discussions.

In organizational and military naming, ordinal numbers denote unit designations. The 28th Infantry Division is an example of a military unit named to reflect its numerical order within a larger structure. Other units or events may similarly use the 28th designation.

In mathematics, the number 28 is notable as a perfect number, the sum of its proper divisors (1, 2, 4, 7, 14) equaling 28. The ordinal 28th, however, primarily serves to indicate position in a sequence, with no special mathematical meaning beyond that ordinal usage.