The Collaborative International Dictionary
Isologous
Isologous \I*sol"o*gous\, a. [Iso- + Gr. lo`gos proportion.] (Chem.) Having similar proportions, similar relations, or similar differences of composition; -- said specifically of groups or series which differ by a constant difference; as, ethane, ethylene, and acetylene, or their analogous compounds, form an isologous series.
Wiktionary
isologous
a. (context chemistry English) Having similar proportions, similar relations, or similar differences of composition; said specifically of groups or series which differ by a constant difference.