'Shortening' definitions:

Definition of 'shortening'

noun

Fat such as butter or lard used in baked goods

noun

Act of decreasing in length; "the dress needs shortening"

From: GCIDE

Shortening \Short"en*ing\, n.
1. The act of making or becoming short or shorter. [1913 Webster]
2. (Cookery) That which renders pastry short or friable, as butter, lard, etc. [1913 Webster]

From: GCIDE

Shorten \Short"en\, v. t. [imp. & p. p. {Shortened ?}; p. pr. & vb. n. Shortening.] [See Short, a.]
1. To make short or shorter in measure, extent, or time; as, to shorten distance; to shorten a road; to shorten days of calamity. [1913 Webster]
2. To reduce or diminish in amount, quantity, or extent; to lessen; to abridge; to curtail; to contract; as, to shorten work, an allowance of food, etc. [1913 Webster]
Here, where the subject is so fruitful, I am shortened by my chain. --Dryden. [1913 Webster]
3. To make deficient (as to); to deprive; -- with of. [1913 Webster]
Spoiled of his nose, and shortened of his ears. --Dryden. [1913 Webster]
4. To make short or friable, as pastry, with butter, lard, pot liquor, or the like. [1913 Webster]
To shorten a rope (Naut.), to take in the slack of it.
To shorten sail (Naut.), to reduce sail by taking it in. [1913 Webster]