mar·a·thon·er 
(mărə-thŏn′ər)
(mărə-thŏn′ər)n.
One that participates in a marathon, especially a marathon runner.
mara·thon′ing n.
- semifinished
- semiflexible
- semifluid
- semifluidity
- semiformal
- semifreddo
- semigloss
- semiglossy
- semigroup
- semihard
- semiheavy water
- semi-independent
- semi-infinite
- semiliquid
- semiliquidity
- semiliteracy
- semiliterate
- Semillon
- semilog
- semilogarithmic
- semilunar
- semilunar bone
- semilunar cartilage
- semilunar valve
- semilunate