How to spell ATNOICITY correctly?

If you meant to type "atnoicity" but realize it's a misspelling, there are several correct suggestions. "Atonicity" refers to the lack of tonicity in a solution. Alternatively, "atoxicity" relates to the absence of toxicity. Both terms refer to different scientific concepts, depending on what you intended to convey.

• Atrocity The massacre that took place was an unimaginable atrocity.
• Tonicity The tonicity of a solution determines the movement of water across a cell membrane.

Attenttion

• attention
• attentions
• attenuation
• inattention