in almost any sutta I have access to, sankhara is translated
as aggregates or formations.
It was explained, that this is done on bases as follow:
Sa.nkhaara is derived from sa.nkharoti: combine, put together, compose
(Thai: prung teng).
but when I check in dictionary of Pali Text Society it states:
Sankhara - "preparation" and "sacrament," also in philosophical
literature "former impression, disposition" Lit. "preparation, get
up"
Aggregate of the conditions or essential properties for a given
process or result -- e. g. (i.) the sum of the conditions or
properties making up or resulting in life or existence;
the essentials or "element" of anything (--°), e. g. ayusankhara,
life--element D II.106; S II.266; PvA 210; bhavasankhara,
jivitasankhara, D II.99, 107. (ii.) Essential conditions,
antecedents or synergy (co--ordinated activity), mental coefficients,
requisite for act, speech, thought: kaya°, vaci°, citta°,
or mano°, described respectively as "respiration,"
"attention and consideration," "percepts and feelings,"
Sankhata - Sankhata [pp. of sankharoti; Sk. sanskrta]
1. put together, compound; conditioned, produced by a combination
of causes, "created," brought about as effect of actions in former
births.
In this way, it seems to me:
1. Sankhata and not sankhara is derived from sankharoti
2. Sankhara emphesizes initiation, preparation and not holding or
bounding together.
3. Sankhata is the one which puts and forms compound.
4. When sankhara is translated as formation, aggregate it actually
does not point to correct moment in process. It points to the moment
after initiation.