Eahta-teóða

According to the Old English Dictionary:

eahta-teóða

m: eahta-teóðe; f. n. adj. The eighteenth; duodevicēsimus :-- On ðam eahtateóðan geáre in the eighteenth year, Ors. 6, 2; Bos. 117, 10. Ðysne eahtateóðan sealm Dafid sang David sang this eighteenth psalm, Ps. Th. arg. 18. eahta-teoða