Latin word rationem comes from Latin reri, Proto-Indo-European *reh₁-, Proto-Indo-European *rh₁-tós, and later Proto-Italic *rēōr (Reckon, calculate.. Think, deem, judge.)
| Dictionary entry | Language | Definition |
|---|---|---|
| reri | Latin (lat) | |
| *reh₁- | Proto-Indo-European (ine-pro) | to put in order |
| *rh₁-tós | Proto-Indo-European (ine-pro) | |
| *rēōr | Proto-Italic (itc-pro) | Reckon, calculate.. Think, deem, judge. |
| *ratos | Proto-Italic (itc-pro) | Established, authoritative. Fixed, certain. |
| reor | Latin (lat) | I reckon, calculate.. I think, deem, judge. |
| ratus | Latin (lat) | ; rat Established, authoritative. Fixed, certain. |
| rationem | Latin (lat) |