元となった辞書の項目
pronephron
noun
(biology)
The
first
part
of
the
urogenital
system
to
be
differentiated
in
a
vertebrate
embryo,
which
functions
as
a
simple
excretory
organ
in
simpler
forms,
serves
as
a
provisional
kidney
in
some
fish
and
amphibians,
and
only
appears
as
a
temporary
embryonic
structure
in
reptiles,
birds,
and
mammals.
意味（1）
(biology)
The
first
part
of
the
urogenital
system
to
be
differentiated
in
a
vertebrate
embryo,
which
functions
as
a
simple
excretory
organ
in
simpler
forms,
serves
as
a
provisional
kidney
in
some
fish
and
amphibians,
and
only
appears
as
a
temporary
embryonic
structure
in
reptiles,
birds,
and
mammals.
