Similar in meaning:
* Producer: This is the most common synonym and emphasizes their role in ecosystems.
* Primary producer: This is more specific and highlights their position at the base of food chains.
* Self-feeder: This emphasizes their ability to produce their own food.
* Photosynthetic organism: This is specific to organisms that use sunlight for energy.
* Chemosynthetic organism: This is specific to organisms that use chemicals for energy.
Related concepts:
* Photoautotroph: A specific type of autotroph that uses sunlight.
* Chemoautotroph: A specific type of autotroph that uses chemicals.
* Troph: This is a broader term that encompasses all organisms based on their feeding strategy.
The best synonym to use depends on the specific context and what you want to emphasize.