zo·o·chlor·el·la 
(zō′ə-klə-rĕlə)
(zō′ə-klə-rĕlə)n. pl. zo·o·chlor·el·lae (-klə-rĕlē)
Any of various one-celled green algae that live symbiotically within the cells of aquatic invertebrate organisms such as sponges and sea anemones or within certain protists.
- atrophic
- atrophy
- atropin
- atropine
- Atropos
- ATSC
- at sea
- at service
- at sign
- Atsina
- at sixes and sevens
- at (someone's) beck and call
- at someone's beck and call
- at (someone's) door
- at someone's door
- at (someone's) feet
- at someone's feet
- at (someone's) service
- at someone's service
- at speed
- at stake
- at stud
- at swords' points
- att.
- attaboy