Verb

(en verb)

To find out definitely; to discover or establish.

* {{quote-book, year=1905, author=

, title= , chapter=1 citation , passage=“There the cause of death was soon ascertained ?; the victim of this daring outrage had been stabbed to death from ear to ear with a long, sharp instrument, in shape like an antique stiletto, which […] was subsequently found under the cushions of the hansom. […]”}}

As soon as we ascertain what the situation is, we can plan how to proceed.

Verb

(deriv)

To obtain or receive (something) from something else.

* {{quote-magazine, year=2013, month=July-August, author= Sarah Glaz

, title= Ode to Prime Numbers , volume=101, issue=4, magazine=(American Scientist) , passage=Some poems, echoing the purpose of early poetic treatises on scientific principles, attempt to elucidate the mathematical concepts that underlie prime numbers. Others play with primes’ cultural associations. Still others derive their structure from mathematical patterns involving primes.}}

(logic) To deduce (a conclusion) by reasoning.

(linguistics) To find the derivation of (a word or phrase).

(chemistry) To create (a compound) from another by means of a reaction.

To originate or stem (from).

* {{quote-magazine, date=2012-01

, author=Robert M. Pringle, volume=100, issue=1, page=31, magazine=(American Scientist) , title= How to Be Manipulative , passage=As in much of biology, the most satisfying truths in ecology derive from manipulative experimentation. Tinker with nature and quantify how it responds.}}

To turn the course of (water, etc.); to divert and distribute into subordinate channels.

* (and other bibliographic details) Holland

For fear it [water] choke up the pitsthey [the workman] derive it by other drains.