The Wikipedia definition is suitable to say that species 1 and 3 share common descent.
Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time.
Any node in a (fully bifurcating) tree that is an ancestor to more than two tips will necessarily contain tips that are also descended from some other node.
OP is correct that "there is a common ancestor at some point," and there is strong evidence that all cellular life arose by common descent from our most recent common ancestor.
In practice, the term is usually limited by context. For example, many more relevant comparisons can be made between roses and apples, than between roses and dogs, even though the ancestor of animals and plants did once exist. In a conversation about energy procurement it wouldn't make sense to reference the common descent between roses and dogs; but in a conversation about, say mitosis, it might.
The term "related" suffers similar ambiguity.
As the figure shows, two species can share many "common ancestors," so it may be necessary to specify the "most recent common ancestor." In the figure, both
B are common ancestors of
A is their most recent common ancestor.
B is the most recent common ancestor of
The thick black line coming down from
B in the figure represents the connection to
B's ancestors. All of those ancestors are common ancestors of
1,2,3, but none are the most recent common ancestor of
The most recent common ancestor of cellular life is the last universal common ancestor.
OP may want to review the term clade for a slightly more precise way to talk about related species. A clade is a group composed of an ancestor plus all and only its descendants.
In the figure:
2 form a clade with
B form a clade.
2) do not form a clade.