1. I usually walk out the door every morning at 7:00 a.m. to go to work.

door

 2. Tina’s cat fell out the window, but it’s okay.

window

 3. There’s a big yard out back.

out back = the backyard

out front = the front yard

backyard
note: The preposition "out" is often used with "of" — "out of" — or the word "out" is used as an adjective or as an adverb, or it’s used with gerunds as seen in the example below.

out + (gerund)

She’s out shopping.

She’s out grocery shopping.

out = outside the house

woman with groceries

The word "out" is often used as an adjective:

We don’t have any more milk. We’re all out.

out = no more

milk

 The lightbulb is out.

out = 1. not working; broken; 2. no electrical power.

lightbulb

 She likes to go out on the weekends.

 She went out last night.

 go out = leave the house

woman

The word "out" is used with many different idioms and expressions and can have many different meanings as an adjective or as an adverb.

For example, the sentence, "He’s out" could mean…

 1. He’s a baseball player playing offense, and he has to leave the field.

 2. He’s openly gay (homosexual). Instead of keeping it a secret, he tells people the truth about himself.

 3. He’s no longer a part of the organization. Someone fired him, told him to leave, or decided not to include him in something.

 4. He’s not in the office. He’s out at lunch, or he’s doing some other activity outside the office.