I am new to the software development and get confused between the unit test and functional test. To me, it looks the same. When writing a unit test, I would put in different input and compare output with an expected one. I was told to write a functional test. Not sure what might be different. Can anyone help?

Unit tests:
Unit tests are written from a programmer's perspective. They ensure that a particular method of a class successfully performs a set of specific tasks. Each test confirms that a method produces the expected output when given a known input.

Functional tests:
Functional tests are written from a user's perspective. These tests confirm that the system does what users are expecting it to.

(quotes are from: Unit Testing versus Functional Tests, do visit the link for more information)

Feed your favourite search-engine with the terms Unit Functional test, there's a ton of information to be found on-line about this subject.

It depends who you ask I reckon.

I have been in the game for over 20 years and I still don't know (or care) what half the bloody jargon means.

One bit of advice is: do NOT be afraid to ask.
Don't keep silent if you don't understand something and pretend you do.
Ask for clarification from peers or boss or client, it doesn't make you look stupid.

You are new, you are not expected to know it all, but you can impress by asking good questions.

I'm off to light my pipe.