implied yuri
When it is being mentioned that a girl has a romantic relationship with another girl, but the relationship is not shown in the image.
For example, a girl might be talking with another female character and showing her affection, but the second girl is not actually present in the picture. Another case may be an image depicting a girl fantasizing, romantically or sexually, about another girl who is just mentioned and not visually shown (Danbooru post #2668953).
Images wherein a female is expressing sexual or romantic affection toward an inanimate object resembling another female can be another example of implied yuri (Danbooru post #6821720).