同 (tóng): same; similar; identical

Meanings

1 same; similar; identical
2 together; with
3 to agree

Characters

同

tóng

same; together

Examples

我们是同学。

Wǒmen shì tóngxué.

We are classmates.

我不同意。

Wǒ bù tóngyì.

I don't agree.

同时做两件事。

Tóngshí zuò liǎng jiàn shì.

Do two things at the same time.

Tips

usage

同 is one of the most productive bound morphemes in Chinese — it stacks onto almost any role-noun to mean 'fellow ___': 同学 (classmate), 同事 (colleague), 同伴 (companion), 同胞 (compatriot). It also pairs with abstract nouns: 相同 (identical), 共同 (common), 不同 (different). Its semantic opposite is 异 (different).

register

Rare second reading 同 (falling tone) is locked to one word and its derivatives: 胡同 (Beijing alley), with 死胡同 (dead-end) and 胡同儿 (erhua form) inheriting the tone. Memory hook: if it's an alley, falling tone; otherwise rising.

Components

radical

口 kǒu

mouth

Inner mouth radical (Kangxi #30) — the indexing radical, sitting under the framing 冂. Anchors the original 'shared meal under one roof' imagery: people eating together = sameness, identity, alignment. 同 forms many bound compounds: 同学 (classmate), 同事 (colleague), 相同 (identical), 同意 (agree).

semantic

冂 jiōng

down-open frame; far border

Outer down-open frame — standalone 冂 is 2 strokes; in 同 it gains an extra inside horizontal, framing the mouth radical inside. Originally depicted a roof under which people gathered to share food (口) — an enclosure of common purpose. The whole char is indexed under Kangxi #30 口 (mouth) inside.