Head = 头 [tóu]
An ostrich has buried its whole head in the ground, leaving only a body, two legs and a neck going into the dirt. The hidden part is its 头.
头 (tóu) means “head.” It is also in 头发 (tóufa), hair, literally “head hair.”
头 is the measure word for some big animals: 一头牛 (yì tóu niú), one cow. A headache is 头疼 (tóu téng) or 头痛 (tóu tòng).
我头疼。 — Wǒ tóu téng. — I have a headache.
他摇了摇头。 — Tā yáo le yáo tóu. — He shook his head.