Can some words that are usually nouns can function as adjectives?

Yes, they are actually known as 'noun as adjective'. Some examples are:

• a history teacher
• a race horse or a horse race
• a home exhibition
• fitness equipment

When a noun as adjective and noun combination becomes commonly used, it is considered a compound noun; some compound nouns that become commonplace in the last few decades are computer monitor, laptop, cell phone, etc.