Help please

[froo]

I am a word which is not used much these days. Although I start and finish with an e I only contain one letter. What word am I?

[scotman]

From the OED

ee,
north. and esp. Sc. form of eye, q.v. for the word and its compounds, ee-bree, ee-list, etc.

'ee.
Colloq. contraction for ye.
1775 Sheridan St. Patr. Day i. i, Hark'ee lads, I must have no grumbling.

[Louise_is_stuck]

envelope?

[factor-fiction]

I like ENVELOPE!