A yard, by definition, opens off of the front of a house: Rashi Eruvin 5a s.v. Batim vaChatzeirot
An alley is longer than it is wide; otherwise, it is a yard: Eruvin 5a, 12b
Whether a yard which has only one house, and that house is less than 4*4 Cubits, is included in requiring the participation of its owners in a communal meal along with the owners of other yards bordering an adjacent alley to permit carrying within it on Shabbat: Succah 3a-b
Status of a yard which is shared by many houses: Eruvin 12b
Status of a yard which is also a major thoroughfare: Eruvin 8a, 22b
Status of a yard which borders on a public area: Eruvin 17a, 94a
Status of a yard which borders on an alley, and has a gap in the wall which ordinarily separates the yard and the alley: Eruvin 7b-8b
Status of multiple adjacent yards which border an alley, and which did not merge with each other: Eruvin 91b
Status of a small yard which opens into a larger yard, either with a gapped wall or without any interruption: Eruvin 8a-b, 9b-10a, 89b, 92a-93a, 93b-94a
Status of a yard with multiple residences which are owned and leased out by a single proprietor, where the proprietor has "Tefisat Yad" - he is capable of storing property there, and of commanding control of sections of the property: Eruvin 85b-86a
Status of an elevated area, such as a post, within a yard [Technically, the yard's 'space' reaches the heavens, but in a public area the post's top would be its own domain]: Eruvin 89a, 90b
The Walls of a Yard
Nullifying a gap in a wall based on the size of the surrounding spaces: Eruvin 11a
How much of a yard's wall must be left on either side of a gap which opens into a public area, to permit transport within: Eruvin 10a, 12a
The method of "Tzurat haPetach," creating the form of an entrance at the opening of an alley to merge the properties within, does not help for a yard: Eruvin 5b, 11a, 12b
What sort of wall is necessary, around a gap which lets in seawater: Eruvin 12a-b
Does a ladder function as an entrance between properties, or as a wall: Eruvin 59b-60a
If the wall around a yard has a gap of up to ten cubits, the wall is still valid as a border: Eruvin 5b, 15b, 76b, 87b, 92a
What happens if a wall separating two yards collapses on Shabbat: Eruvin 17a, 93b-94a
What happens if one side of a yard opens into a public area on Shabbat: Eruvin 94a
Where both sides of a yard open into a public area on Shabbat: Eruvin 94a-95a