Physical states with ter (ter fome, ter frio)

Portuguese HAS Hunger, It Is Not Hungry

This is one of the first places Portuguese parts company with English. Where English uses to be plus an adjective — I am hungry — Portuguese uses ter plus a NOUN:

Because the complement is a noun, it never agrees with you: a woman says tenho frio, not tenha fria. And because it is a noun, you intensify it with muita or muito, not with very: tenho muita fome, tenho muito frio.

The Nouns on Their Own

a sede and o sono are ordinary nouns outside the expression, and you will meet them that way too. Note that sede is feminine and sono masculine, which is what decides between muita sede and muito sono.

Fear Takes a Preposition

ter medo de — to be afraid of — adds de, and de contracts with a following article exactly as it always does: medo do cão, medo da água.

One warning about calor. Tenho calor is what a PERSON feels. To say the WEATHER is hot Portuguese uses a different verb — faz calor — and that comes later.