Wiktionary
n. (context biology English) A microbe that takes energy from reduced compounds of minerals.
Wikipedia
A lithoautotroph is a microbe which derives energy from reduced compounds of mineral origin. They may also be referred to as chemolithoautotrophs, a type of lithotrophs, reflecting their autotrophic metabolic pathways. Lithoautotrophs are exclusively microbes; macrofauna do not possess the capability to utilize mineral sources of energy. For lithoautotrophic bacteria, only inorganic molecules can be used as energy sources. Most lithoautotrophs belong to the domain Bacteria. The term "Lithotroph" is created from the terms 'lithos' (rock) and 'troph' (consumer); literally, it may be read "eaters of rock." Many lithoautotrophs are extremophiles, but this is not universally so.
Lithoautotrophs are extremely specific in using their energy source. Thus, despite the diversity in using inorganic molecules in order to obtain energy that lithoautotrophs exhibit as a group, one particular lithoautotroph would use only one type of inorganic molecules to get its energy.