A loose grouping of a few thousand stars is called a cluster. The stars in a cluster have similar characteristics, which means that they have a common origin.
I think you are referring to a cluster of stars.
A loose grouping of a few thousand stars is called an open star cluster. These clusters typically contain young stars that formed together from the same molecular cloud. Open star clusters are held together by gravity and can be disrupted over time by interactions with other objects in space.
A grouping of stars with a loose and disorganized appearance, containing no more than a few thousand stars, is called an open cluster. These clusters are typically young and are held together by gravitational forces. They are spread out across the sky and are great objects for amateur astronomers to observe.
A misty group of stars is referred to as a star cluster. Star clusters are groups of stars that are gravitationally bound together and can be classified as either open clusters (loose grouping of stars) or globular clusters (more densely packed grouping of stars).
A grouping of stars is called a constellation. Constellations are patterns of stars in the sky that are named after mythological figures, animals, or objects. They help us navigate the night sky and tell stories from different cultures.
An apparent grouping of stars (as the Big Dipper) is an asterism, formerly called a constellation. (A constellation is now a bordered area of sky, equivalent to a state on a political map). Stars which are actaully associated, may be a cluster, a nebula or a galaxy.
I think you are referring to a cluster of stars.
Common groupings of stars within a constellation, or which overlap two or more constellations, are called "asterisms". For example, "Orion's Belt" is a smaller grouping within Orion, and the Big Dipper is a smaller grouping within Ursa Major, the Great Bear.
The group of stars found in the constellation Leo is called the "Sickle," which forms the lion's head. It is a distinctive grouping of stars that is easily recognizable in the night sky.
The word for stars that do make a pattern is "asterism" (not constellation; that's actually defined differently). There isn't really a word for a group of stars that don't make a pattern, because there's no such thing: any arbitrarily chosen group of stars will make a pattern, even if that pattern is essentially random.
Galaxies.
Galaxies.