the sheets. Is this a plural word? it ends with "a"... and if so, what is the singular? lenzuolo? is it masculine or feminine?
Lenzuolo is masculine and its plural is lenzuola, feminine. There's a bunch or words like that: http://italian.about.com/library/fare/blfare169a.htm http://www.lifeinitaly.com/italian/nouns-gender (See No. 8)
The link given by the "viaggiatore" is very well done. If you go to "Italian Nouns With Two Forms of the Plural", among all the others you will find Lenzuoli/lenzuola ( the termination in "a" is a form of L. neuter plural). "Lenzuola" are only the two sheets "in use" in our bed. The E. "to slip under the blankets" is the I. " cacciarsi sotto le lenzuola". The "lenzuoli" are the sheets that can be found in a chest, in a wardrobe. In past times, a bride could bring a dowry of a dozen of lenzuoli, not lenzuola. Also other plurali sovrabbondanti (=superabundant) have the plural in "a" when referring to couple often parts of human body (labbra, ginocchia..)