Co-sleeping refers to a practice where the child and the parent sleep close to each other. It could mean bed-sharing or room-sharing.
Bed-sharing refers to the parents and child sleeping in the same bed, or together on a couch, chair, or a mattress on the floor.
Room-sharing is when a child sleeps on a separate surface but in the same room as the caregiver. So, there could be a crib for your baby in the same room you sleep in.
Co-sleeping is generally considered a safe practice and begins at 1 year of age for most children.