Definition of estimating:
(n) :
A rough calculation or assessment of the value, size, or cost of something.
(n) :
(specifically in business and construction) A document (or verbal notification) specifying how much a job is likely to cost.
(v) :
To calculate roughly, often from imperfect data.
(v) :
To judge and form an opinion of the value of, from imperfect data.
(n) :
An upper limitation on some positive quantity.
(adj) :
(obsolete, rare) estimated