Which term do you use? Does it matter?

In some cases, it means a great deal how you word your proposal to a client. Calling your proposal an estimate, job quote or statement of work (SOW) can mean different things to the client, and to the law. 

As estimate is a "guestimate" or an approximation. Estimates are flexible and in most cases, negotiable.
A quote provides your client with an exact price for the job or project. Quotes are exact, and in some cases, more legally binding than an estimate.
A Statement of Work seeks to define liabilities, responsibilities and work agreements between two parties. It allows you to manage expectations and add a layer of detail about what the project will and will not cover.

=== Other links for items mentioned in this show
Techcon Unplugged: https://techconunplugged.com/
Use discount code ITBP75OFF and save $75 off the ticket price.

Law Office of Bradley Gross: https://bradleygross.com/