What meaning does the title have, and why did the author use that particular spelling of rime? this is all one question

Rime is an archaic (old, outdated) spelling of rhyme (“poem”). When first published in Lyrical Ballads in 1798, the poem’s original title was Rime of the Ancyent Marinere. Coleridge used many archaic words and spellings throughout the poem, including rime. In later versions of Lyrical Ballads, many of these archaic words in Rime of the Ancient Mariner were edited out, and the marginal glosses (brief explanations) were added.

Some Coleridge scholars believe that rime is also a play on the word’s other meaning: “frost.” They believe that the poem is based, in part, on the second voyage of British explorer James Cook, who ventured into the Arctic Circle in the 1770s.