muisteissa
Muisteissa is not a standard Finnish word. In most cases it is regarded as a misspelling or nonstandard variant of muistoissa, the inessive plural form of muisto meaning “in memories.” The normative form to express the idea of being located within memories is muistoissa. The existence of muisteissa as a word in ordinary writing is therefore rare and typically considered erroneous in formal contexts.
Etymology and morphology: muisto means a memory or memory of a past event, and its inessive plural
Usage notes: When aiming for correct written Finnish, use muistoissa to convey the idea of being located
Related terms: muisto (memory), muistit (memories), muistoissa (in memories). See also muisti (memory) and Finnish noun
See also: muisto, muistit, muistoissa, Finnish grammar, Finnish orthography.