A barrow is essentially a mound of earth over one or more burials. They are more usually to be dated to the Bronze Age. There are many forms of barrow including ring, bowl, long and bell barrows.

Ring barrows are formed by digging a circular trench or fosse around a central burial, with no mound.

Bowl barrows are formed by heaping up soil over the burial(s) from a surrounding fosse, these often have an external bank too (see Ballyremon Commons (County Wicklow)).

Bell barows are simply round mounds with no fosse or external bank.

Long barrows are rare in Ireland and are more common in southwest England. Their shape is basically ovoid rather than round (see Ballynoe (County Down))

A compartment in a tomb in which burials were placed. In court tombs and wedge tombs a chamber is a sub-division of the burial gallery. Portal tombs have single chambers and passage tombs can have anything from one to five chambers, although usually passage tombs are considered to have a main chamber with extra subsidary chambers.

A cairn is a large pile of stones, quite often (but not always) containing a burial. Sometimes they have a kerb around the base.

Most cairns are hemi-spherical (like half a football), but the piles of stones used to cover wedge tombs, court tombs and portal tombs are also called cairns. When associated with these types of monument they are not always round, but sometimes rectangular or trapezoidal.