The hectometre, (SI symbol: hm ), spelt hectometer in American and Philippine English, is a unit of length in the International System of Units (SI), equal to one hundred metres and to one tenth of a kilometre. The word comes from a combination of "metre" and the SI prefix "hecto-", meaning "hundred". It is not commonly used in English. A football field (either soccer or American) is approximately 1 hectometre in length. The hectare (ha), a common metric unit for land area, is equal to one square hectometre (hm2). The hectometer has sometimes been used for expressing the distance to a target in warfare.