词 cí = 讠 (yán, speech) + 司 (sī, the phonetic). The left element 讠 is the compressed simplified form of 言 yán, the speech radical that marks words about talking, naming, and language. The right element 司 sī supplies the sound and once carried a sense of taking charge of or managing affairs. As a structure 词 is a 形声字 (xíngshēngzì), a sound-and-meaning compound: the radical tells you it concerns speech, and 司 gives the approximate reading.

The traditional glyph is 詞, with the full 言 on the left; the simplified 词 trims 言 to the three-stroke 讠 but keeps the same 司 on the right. Simplified and traditional name the same character.

From the core idea of a managed piece of speech, three senses branch out:

1. A word or term. The basic unit of vocabulary, larger than a single character: 词语 cíyǔ (words and expressions), 生词 shēngcí (a new vocabulary word), 单词 dāncí (an individual word).
2. Wording, diction. The words a speaker or writer chooses: 台词 táicí (an actor lines), 歌词 gēcí (song lyrics), 致辞 zhìcí (to deliver an address).
3. The classical 词. A lyric-poem form that flourished in the Song period, written to fixed tune-patterns and meant to be sung, set apart from 诗 shī, the regulated verse of the Tang.

The thread through every sense is words as crafted, chosen, fitted to a purpose: the dictionary entry, the line an actor speaks, the syllable laid onto a melody. 词 is always speech that has been shaped into a unit.

When grammarians name the categories of words, they stack a descriptive character in front of 词. The 词 supplies "class of word," and the first character says which class. So 名词 míngcí is the "name-word," a noun; 动词 dòngcí is the "moving-word," a verb; 形容词 xíngróngcí is the "form-describing word," an adjective; 量词 liàngcí is the "measuring word," the classifier that goes between a number and a noun.

The same template runs through the whole grammar: 副词 fùcí (adverb), 代词 dàicí (pronoun), 介词 jiècí (preposition), 连词 liáncí (conjunction), 助词 zhùcí (particle). Learn that 词 here means "part of speech" and a long list of grammar terms becomes transparent at a glance. You may notice 词 doing this very job in the gloss boxes throughout this site: every POS tag, from 名词 to 动词, is built on it.

The third life of 词 is the words people choose and sing. In everyday use it names the wording itself: 歌词 gēcí is the lyrics of a song, 台词 táicí is the lines an actor speaks on stage, 贺词 hècí is a few words of congratulation. In each, 词 is the chosen language fitted to a moment.

This same sense rose to high literature in the classical 词, the lyric form that flourished in the Song. Unlike 诗 shī, the regulated verse perfected in the Tang with its even lines and fixed length, a 词 is written to a 词牌 (cípái), a named tune-pattern that dictates the number of lines, the count of characters in each, and the placement of tones. The poet does not invent the shape; the poet "fills in words," 填词 tiáncí, onto a melody already known by name. The lines run uneven, the music carries them, and the result reads more intimate and song-like than the stately 诗. Song lyric, 宋词, stands beside Tang verse, 唐诗, as one of the twin peaks of classical Chinese poetry.

Read 词 as speech, 讠, taken in hand and managed, 司. That is the whole character: a piece of language someone has charge of and has shaped to a purpose. From there the three senses fall out naturally. The unit you look up and learn is a word (生词, 单词). The label grammar hangs on a class of words is the part of speech (名词, 动词). And the words a singer or actor or poet chooses are the diction (歌词, 台词), rising to art in the classical sung lyric.

Keep 字 and 词 apart and you will rarely go wrong: 字 is the symbol on the page, one glyph; 词 is the meaning it helps build, one word. Count glyphs with 字, count words with 词.