Airplane splits into air and plane, backyard into back and yard, and campfire into camp and fire, so each one is a compound word. Market, silver, and garden cannot be broken into two smaller words, so they do not belong in the compound group.

If you split airplane, you see the word air and the word plane inside it. A plane flies through the air, which is why joining these two words makes sense.

Joining the words back and yard gives you backyard, the yard at the back of a house. The meaning comes straight from the two smaller words.

A campfire is a fire that people build when they camp outside. Saying camp plus fire out loud shows how the two smaller words come together to name it.

Every compound word is built from exactly two smaller words, like sun and shine becoming sunshine. That is the rule that tells us a word is compound.

Putting the words camp and fire side by side makes the new word campfire. You can hear both smaller words clearly when you say it.

True — airplane breaks apart into two real words, air and plane, which means it fits the rule for a compound word.

False — market cannot be split into two smaller real words. Mar and ket are not their own words, so market does not follow the compound word rule.

True — if you say backyard slowly, you can hear the word back at the start and the word yard at the end. Together they name the yard behind a house.

False — a compound word is made of exactly two smaller words, not three. Words like sunshine, raincoat, and backyard each join just two parts together.