What are we estimating? Lead times (calendar time until in production) from time asked for estimate? Lead times from the time the work begins (since sometimes

What are we estimating? Lead times (calendar time until in production) from time asked for estimate? Lead times from the time the work begins (since sometimes the time the estimate is made and the time when the development starts can have gaps, sometimes small, sometimes large)? Developer/development effort (in "man hours")? Each estimate is important and has it's own use(s). What estimates do people tend to provide here?