fold 1 
(fōld)
(fōld)v. fold·ed, fold·ing, folds
v.tr.
1. To bend over or double up so that one part lies on another part: fold a sheet of paper.
2. To make compact by doubling or bending over parts: folded the laundry; folded the chairs for stacking.
3. To bring from an extended to a closed position: The hawk folded its wings.
4. To bring from a compact to an extended position; unfold: folded the ironing board down from the wall; folded out the map to see where we were.
5. To place together and intertwine: fold one's arms.
6. To envelop or clasp; enfold: folded his children to his breast; folded the check into the letter.
7. To blend (a light ingredient) into a heavier mixture with a series of gentle turns: folded the beaten egg whites into the batter.
8.
a. Informal To discontinue operating; close: They had to fold the company a year after they started it.
b. Games To withdraw (one's hand) in defeat, as by laying cards face down on a table.
9. Geology To form bends in (a stratum of rock).
v.intr.
1.
a. To become folded.
b. To be capable of being folded: a bed that folds for easy storage.
2. Informal To close, especially for lack of financial success; fail.
3. Games To withdraw from a game in defeat.
4. Informal
a. To give in; buckle: a team that never folded under pressure.
b. To weaken or collapse from exertion.
n.
1. The act or an instance of folding.
2. A part that has been folded over or against another: the loose folds of the drapery; clothes stacked in neat folds.
3. A line or mark made by folding; a crease: tore the paper carefully along the fold; a headline that appeared above the fold.
4. A coil or bend, as of rope.
5. Chiefly British A hill or dale in undulating country.
6. Geology A bend in a stratum of rock.
7. Anatomy A crease or ridge apparently formed by folding, as of a membrane; a plica.
[Middle English folden, from Old English fealdan, faldan; see pel-2 in the Appendix of Indo-European roots.]
folda·ble adj.
fold1top: isocline fold
center: overturned fold
bottom: recumbent fold