cat·e·nane 
(kătə-nān′)
(kătə-nān′)n.
A complex organic molecule containing two or more macrocyclic ring structures intertwined like links of a chain.
[Latin catēna, chain + -ANE.]
- first responder
- first run
- first-run
- first sergeant
- first strike
- first-strike
- first string
- first-string
- first thing
- first thing
- first-timer
- first water
- First World
- First-World
- First World War
- firth
- fisc
- fiscal
- fiscally
- fiscal year
- Fischer
- Fischer-Dieskau
- Fischer projection
- Fischer projection formula
- fish