- Dear Reji
The word used for "Knooma" in English is Hypostases.
"Knooma" is syriac and was taken over to malayalam.
See the trinitarian concept as explainde by Bar ebroyo:
According to Bar Ebroyo, God of Christians is the
Holy Trinity consisting of the Father, the Son and
the Holy Spirit. He affirms that God is one Ousia and
three hypostases, meaning that the one Godhead is
eternally and equally individuated in perfection in
the three persons of the Father, the Son and the Holy
Spirit. But they are not three gods, because each of
them has the same Godhead in Him. The Ousia, namely
the Godhead, is not divided; neither does it exist by
itself apart from the three persons or the hypostases.
God is one in His Ousia or Nature, because He is
necessary and not merely possible. "If God is more
than one nature, each one of them should find itself
to be composed of two constitutive parts, that is to
say, of genus and of species. All that which is
composed is only possible and not necessary. Therefore,
if there were two gods, they should have been only
possible and not necessary. Everything, which possesses
a possible nature, is not God. So the divine nature,
which is the necessary existence is necessarily one."
The creator is wise and live through wisdom and life.
But these determinations of God are not accidents,
because then God will be the seat of accidents and will
be subject to change. Wisdom and life are therefore
essential components of God; they are hypostases. Now
as the concept of one wise and live is something other
than wisdom and life, the creator God Himself is also
one real hypostasis, to which life and wisdom belong.
And here shines the light of the trinity of hypostases
of the unique divine nature. 
Even though wisdom and life are distinct and real
hypostases, they are inseparably and indivisibly united
to the hypostasis to which they belong. Since, without
such a third hypostasis, wisdom and life would be the
wisdom and life of nothing. Consequently, they are
neither divided nor separated, although in the strict
logical sense the hypostases differ through their
corresponding predicates. The theology designates
"as Father the hypostasis which is wise and live, as
Son the wisdom and as Holy Spirit the life." Although
both Son and Spirit are caused from the Father, there
is difference in the manner of generation. The
peculiarity of the Son is "begetting" and that of the
Spirit is "procession." Nevertheless, all the three
hypostases have only one substance or nature, but even
when each of these three hypostasis is called God,
they will not be defined as three gods or three
divinities, because this expression will lead one to
divide the nature or Ousia of God into three. The
three hypostases are not three gods, because the
concepts that they characterize, namely to generate,
to be generated and to proceed, are relative concepts
and they are referring themselves to the being. That
is to say: "The multiplicity of relations does not
lead to multiplicity of the natures." And consequently,
the Son and the Spirit are not created and brought
forth, because then both of these would have been
creatures and would differ from the nature of the
Father. But the three hypostases possess only one nature,
which is common to all the three.
"Prayers and Fasts according to Bar Ebroyo,
A study on the prayers and fasts of the oriental
churches" Fr. Dr. Biji Chirathilattu,
Lit Publications in Münster, Germany
 Le Candélabre III, p. 562f. Cf. KAWERAU: Christentum,
pp. 71-75 and PANIKKER: Christology, p. 308 and 317f
also for a brief account of Bar Ebroyo's understanding
of trinity and incarnation.
 Le Candélabre III, p. 556. Cf. supra, II.1.2,
p. 22f also.
 Ibid., p. 564.
 Ibid., p. 568.
 Ibid., p. 572.
 This may be the reason (i.e. that each of them can be
called God), why while addressing the prayers Bar Ebroyo
often interchanges the addressees between Father and Son.
For example among the eight petitions given in the
Ethicon I: 2:3, the first, second and last are addressed
to the Father, whereas others are addressed to Jesus.
Cf. Ethicon (ed. TEULE), pp. 27-29.
 Le Candélabre III, p. 574.
 Ibid., p. 576.
 Ibid., pp. 592-594.
With Love and Prayers
Fr.Dr.Biji Chirathilattu , Vicar,
St.Mary's Syrian Orthodox Congregation Vienna