liminal

Intermediate between two states, conditions, or regions; transitional or indeterminate.

Existing at the limen. Used of stimuli.

Pertaining to the threshold or entrance; hence, relating to the beginning or first stage; inceptive; inchoative.

Specifically In psychophysics, pertaiuing to the stimulus limen or differential limen. See limen.

of or pertaining to a limen, especially a sensory threshhold.

marginally perceptible.

Pertaining to a threshold or entrance.

Relating to a beginning or first stage of a process; inceptive; inchoative; marginal; insignificant.