Foundling

I came across this word while reading the Stillwell's book. I was reading the biography of d' Alembert and the sentence in which this word popped up is

"His mother abandoned him at birth near the church of St. Jean-le-Rond in the cloisters of Notre Dame, and so he was christened Jean le Rond, following the customs for foundlings"

As usual a quick search on google gives

 

Dictionary.com gives the definition of foundling as

A deserted or abandoned child of unknown parentage.