(noun) "enclosure for cultivation of fruit-trees"
The word comes from Latin hortus, garden, and in the Middle Ages it developed a particular sense related to fruit-growing alongside its general use. Either sense is possible in Shakespeare, but the general sense is the more likely unless a specific reference is made to fruit, as when Shallow talks about eating "a last-year's pippin" in his orchard (Henry IV Part 2, V.iii.2). There seems to be no particular reason to be thinking of fruit trees when Pandarus invites Troilus to "walk here i'th' orchard"
(Troilus and Cressida, III.ii.15), or Sir Toby tells Sir Andrew to look for Cesario (Viola) "at the corner of the orchard" (Twelfth Night, III.iv.174).
There are some quite famous orchard scenes. The Ghost of Hamlet's father tells his son that he was killed while "sleeping in my orchard" (Hamlet, I.v.35). Juliet is surprised to see Romeo, because "the orchard walls are high and hard to climb" (Romeo and Juliet, II.ii.63). And Antony tells the people of Rome that the murdered Julius Caesar has left them in his will "his private arbours, and new-planted orchards" (Julius Caesar)