On Wed, Aug 9, 2017 at 12:01 PM, Jeremy Silver <jp.silver@tiscali.co.uk> wrote:

Have several thesauri? thesauruses? yes them... on my desktop. But do they
define words as used in the 1800s?

Khan's use of "task" is still current.
Merriam-Webster.com has the definition "to oppress with great labor".
Dictionary.com gives "to subject to severe or excessive labor or exertion; put a strain upon (powers, resources, etc.)".
The OED website says "Make great demands on (someone's resources or abilities)".
None of those are listed as archaic meanings.