Both Uses of

adopt
in
Ulysses, by James Joyce

Certainly in every public work which in it anything of gravity contains preparation should be with importance commensurate and therefore a plan was by them adopted (whether by having preconsidered or as the maturation of experience it is difficult in being said which the discrepant opinions of subsequent inquirers are not up to the present congrued to render manifest) whereby maternity was so far from all accident possibility removed that whatever care the patient in that all hardest of woman hour chiefly required and not solely for the copiously opulent but also for her who not being sufficiently moneyed scarcely and often not even scarcely could subsist valiantly and for an inconsiderable†
Chpt 14

adopted = took on as one's own

Kalipedia, he prophesied, would soon be generally adopted and all the graces of life, genuinely good music, agreeable literature, light philosophy, instructive pictures, plastercast reproductions of the classical statues such as Venus and Apollo, artistic coloured photographs of prize babies, all these little attentions would enable ladies who were in a particular condition to pass the intervening months in a most enjoyable manner.†
Chpt 14 *

Definition:

to take on as one's own

The exact meaning of adopt depends upon its context. For example:

"adopt a child" -- to legally take on parental responsibilities for another person's child
"adopt a plan" -- to accept or begin to use something
"adopt a pet" -- to take in a pet -- especially one from an animal shelter
"Congress adopted the resolution." -- had a formal vote and passed
"adopted a confident attitude" -- took on or displayed