fosterage

Rejoined Aslan, "O Commander of the Faithful, he is no father of mine, save by right of fosterage; my father was none other than Ala al-Din Abu al Shamat."

From The Book of the Thousand Nights and a Night — Volume 04 by Sir Richard Francis Burton

Indeed, I repent me of what was done by me to her, for that, in any case, she is my nurse and hath over me the right of fosterage.

From The Book of the Thousand Nights and a Night — Volume 07 by Sir Richard Francis Burton

A child in fosterage was reared and educated suitably for the position it was destined to fill in life.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 4 "Bradford, William" to "Brequigny, Louis" by Various

He has come to claim, as gossip-law allows, the fosterage of MacWilliam's son.

From The Catholic World; Volume I, Issues 1-6 A Monthly Eclectic Magazine by E. Rameur

The terms of fosterage seem to vary in different islands. 

From Journey to the Western Islands of Scotland by Samuel Johnson