The last vowel at the end of mantra-s called yājya , when used in sacrificial works is pluta and has the acute accent (udātta).,
Thus स्तोमैर्विधेमाग्नये३ (Rig. VIII. 43. II), जिह्वामग्ने चकृषे हव्यवाहा३म् (Rig. X. 8. 6).
Why do we say 'at the end'? There are some Yajya hymns, consisting of several sentences. The final vowel (टि) of every sentence would have become pluta, in such a hymn. To prevent it, the word \anta\ is used, so that the final vowel of the hymn at the end of all, becomes pluta.,