If a person is in the process of adjusting status to permanent resident while residing in the U.S., can the person work with a Taxpayer Identification Number (TIN) instead of a Social Security Number (SSN)?

You cannot use an ITIN to work, it's illegal to do so. ITIN tax purposes only.

Hmmm, if a TIN is for tax purposes, and you cannot work with a TIN, then what's the point/purpose of a TIN?

You can us it for filing joint taxes with your US spouse as I do. It's also used for people who aren't USC's but have/or do business in the USA and are required to file US taxes.

I-TIN no. is for dependant(s) of someone that has a working visa, and valid/legal S.S. number, so he or she can claim these dependant(s) for tax purposes, which is most of the time better, bigger refund.

I-TIN is for someone applying for student visa, which is right now, not too easy to get.

I-TIN is never to be use for acquiring a job.

The person can file for EAD - employment authorization document when he files for the AOS - adjustment of status. Once the EAD arrives, he can visit the social security agency and apply for a social security number.

'Cielo' is right, I am a dependant. My parent has a work permit and works. So I guess that is how I have a TIN. Thank you everyone for helping me understand the purpose of a TIN.

I want to work now that I am older, but I don't have a SSN. I don't know what 'passingby' means by filing an EAD application, but does that give the person a work permit and SSN?

'passingby' said that the EAD application needs to be filed during the AOS application, but what if the AOS has been filed years ago by your parent?

Is there a special working application, or EAD, for a child dependant who is an adult now?

I honestly don't know, but it seems to me that as you have an AOS pending (filed by your parent) I presume that you can file an I-765 for an EAD now that you are an adult. The EAD will allow you to get an SS# and work.

http://www.immigration.gov/graphics/formsfee/forms/i-765.htm