Originally, locking scripts were encoded directly in the output script that a transaction credited, you could see them. With Pay to Script Hash (P2SH) the funds are locked to the hash of the full redeemscript instead. The script is no more published, you publish the hash of the script !
In order to spend this bitcoin, the script and the conditions it requires must be provided.
Yes, P2SH outputs lock bitcoin to the hash of a Bitcoin Script.