In your observations of microscopic slides of cartilage and bone, you can see that chondrocytes and osteocytes are both encased in lacunae.

Chondrocytes

Cells found within cartilage tissue that are responsible for the synthesis and maintenance of the cartilaginous matrix.

Osteocytes

Osteocytes are mature bone cells formed from osteoblasts that have embedded themselves in the bone matrix; they maintain bone tissue structure and communicate with other bone cells.

Lacunae

Small spaces or cavities within bone or cartilage tissue that house cells.