Dear Pali friends,

Being interested in the meaning of 'nimitta' in the context of
samadhi, I have made some further research on this subject.

The term 'nimitta' is mentioned in AN 2.16 = DN 3.225:

14. ⌠Cattaarimaani, bhikkhave, padhaanaani. Katamaani cattaari?
Sa.mvarappadhaana.m, pahaanappadhaana.m, bhaavanaappadhaana.m,
anurakkha.naappadhaana.m. Katama~nca, bhikkhave, sa.mvarappadhaana.m?
Idha, bhikkhave, bhikkhu cakkhunaa ruupa.m disvaa na nimittaggaahii
hoti naanubya~njanaggaahii┘
┘
⌠Katama~nca, bhikkhave, anurakkha.naappadhaana.m? Idha, bhikkhave,
bhikkhu uppanna.m bhaddaka.m samaadhinimitta.m anurakkhati
a.t.thikasa~n~na.m pu.lavakasa~n~na.m viniilakasa~n~na.m
vicchiddakasa~n~na.m uddhumaatakasa~n~na.m. Ida.m vuccati, bhikkhave,
anurakkha.naappadhaana.m. Imaani kho, bhikkhave, cattaari
padhaanaanii■ti.

Here we see that 'nimitta' is closely related to perception, and the
monk, seeing a form, hearing a sound, etc., does not cling to it. Note
that nimitta is not limited to visual perception. Next, we see, that
in the context of samadhi nimitta is the apperception (sa~n~naa) of
the object of samadhi.

How can we reconcile these aspects of meaning?

The passage from Visuddhimagga (XIV 130) gives the clue:

"sabbaa va sa~njaanana-lakkha.naa, tad ev▓etan ti puna
sa~njaanana-paccaya-nimitta-kara.na-rasaa daaru-aadiisu tacchakaadayo
viya, yathaa-gahita-nimitta-vasena abhinivesakara.na-paccupa.t.thaanaa
hatthi-dassaka-andhaa (udaa. 54) viya,
yathaa-upa.t.thita-visaya-pada-.t.thaanaa ti.na-purisakesu
miga-potakaana.m purisaa ti uppanna-sa~n~naa viyaati."

"All (sa~n~naa) has the characteristic of recognition (sa~njaanana);
its property is the making of perceptual image (nimitta) that is a
condition of recognizing again, 'this is the very same thing' - as
carpenters and so on do with the wood, etc.; its manifestation is the
producing of conviction by virtue of a perceptual image (nimitta) that
has been accordingly learnt - like the blind perceiving the elephant
( http://www.accesstoinsight.org/canon/sutta/khuddaka/udana/ud6-04.html );
its basis is whatever object that has come near - like the
apperception (sa~n~naa) 'people' that arises for young animals in
respect of scarecrows."

Hence, 'nimitta' is the image one forms in the process of apperception
(sa~n~naa), used to recognize the object in the future. In
psychological terms it is a 'perceptual image' or 'representation'.

What it has to do with samadhi? In Mohavicchedani (Mya: .161) we read:

"Samathova ta.m aakaara.m gahetvaa puna pavattetabbassa samathassa
nimittanti samathanimitta.m."

"The perceptual image of calm (samatha) is a perceptual image used to
produce calm again when one has already learnt the appearance of
calm."

The principle of recognition is applied in the practice of samadhi, when
practitioner reaches the jhana again with the help of learnt
perceptual image of it.

Metta,
Dimitry