한자 (pronounced [한짜]) are the Chinese characters behind many Korean words used in modern Korean. Being aware of them helps with guessing word meanings and retention of new vocabulary.
火 (화) as a character has two main English meanings, fire and anger, and is used in many words related to these concepts. When 火 is used by itself as a word, it almost always means anger. 火 as a radical that appears in many other 한자, such as 炎 (염, flame) or 災 (재, disaster). Below are some common words including the character 火.
火 as in fire:
火災 (화재): a fire, conflagration (such as a fire in a building, a plane on fire).
Characters: 1. 火. 2. 災 (재) as a character means disaster, such as in the word 災殃 (재앙, a disaster).
Recipe: Fire 火 + disaster 災 = a fire, conflagration 火災.
Notes: Seen frequently in news articles, e.g., “러시아 여객기 비상착륙 중 화재(火災)로 41명 숨져” (41 people dead in a fire during the emergency landing of a Russian passenger plane; source: 한국일보).
火山 (화산): a volcano.
Characters: 1. 火. 2. 山 (산), a mountain.
Recipe: Fire 火 + mountain 山 = volcano 火山.
火傷 (화상): a burn, a scald.
Characters: 1. 火. 2. 傷 (상) in general means hurt and is used in words like 傷處 (상처, injury/wound) or 속傷하다 (속상하다, to be upset/feel bad).
Recipe: Fire 火 + hurt 傷 = a burn 火傷.
火曜日 (화요일): Tuesday, or the day of fire.
Notes: In English and Latin languages, Tuesday is the day of the god of fire, Tiw (Old English) or Mars (Latin). In Korean however, the meaning is based on the planet Mars, the red planet of fire.
消火 (소화): fire extinguishing, firefighting.
Characters: 消 (소) means to become extinct.
Recipe: To become extinct 消 + fire 火 = Fire extinguishing 消火.
Compound words: 消火 (소화) is frequently seen in other words related to fire extinguishing; the most commonly encountered in daily life are probably 消火器 (소화기, fire extinguisher) and 消火栓 (소화전, fire hydrant).
Synonyms and similar words: 鎭火 (진화) is a synonym of 消火 (소화). A similar word to 消火 (소화) is 消防 (소방), firefighting that also includes prevention (豫防, 예방), used in words like 消防署 (소방서, fire station), 消防官 (소방관, fireman), and 消防車 (소방차, firetruck).
Homonyms: The pronunciation of this word is the same as digestion (消化; 소화); context should make clear what the underlying meaning is.
消火器 (소화기): fire extinguisher.
Characters: 器 (기). One of the meanings of 器 (기) as a character is a device, such as in the word 器具 (기구, device).
Recipe: Fire extinguishing 消火 (as seen above) + device 器 = fire extinguisher 消火器.
消火栓 (소화전): fire hydrant.
Characters: One of the meanings of 栓 (전) as a character is a sort of tap, faucet (마개).
Recipe: Fire extinguishing 消火 (as seen above) + tap 栓 = fire hydrant 消火栓.
火 as in anger:
火 (화): anger, rage.
火나다 (화나다): to be angered, irritated.
Notes: Very commonly used in daily speech, to ask if somebody is angry: 화났어?
火病 (화병 [화뼝]): a mental illness specific to Korea.
Notes: Korean society often causes Koreans to bottle up their anger (火, 화) and resentment instead of expressing it; in some people, this causes 火病 (화병) with a specific set of characteristics that makes this illness specific to Korea. Read more about 火病 (화병).