Definition of Micrometer
Mi`crom´e`ter
n.
1.
An
instrument
,
used
with
a
telescope
or
microscope
,
for
measuring
minute
distances
,
or
the
apparent
diameters
of
objects
which
subtend
minute
angles
.
The
measurement
given
directly
is
that
of
the
image
of
the
object
formed
at
the
focus
of
the
object
glass
.
Circular micrometer
a
metallic
ring
fixed
in
the
focus
of
the
object
glass
of
a
telescope
,
and
used
to
determine
differences
of
right
ascension
and
declination
between
stars
by
observations
of
the
times
at
which
the
stars
cross
the
inner
or
outer
periphery
of
the
ring
.
Double image micrometer
a
micrometer
in
which
two
images
of
an
object
are
formed
in
the
field
,
usually
by
the
two
halves
of
a
bisected
lens
which
are
movable
along
their
line
of
section
by
a
screw
,
and
distances
are
determined
by
the
number
of
screw
revolutions
necessary
to
bring
the
points
to
be
measured
into
optical
coincidence
.
When
the
two
images
are
formed
by
a
bisected
object
glass
,
it
is
called
a
divided-object-glass micrometer
,
and
when
the
instrument
is
large
and
equatorially
mounted
,
it
is
known
as
a
heliometer
.
Double refraction micrometer
a
species
of
double
image
micrometer
,
in
which
the
two
images
are
formed
by
the
double
refraction
of
rock
crystal
.
Filar micrometer
See
under
Bifilar
.
Micrometer caliper
(Mech.)
a
caliper
or
gauge
with
a
micrometer
screw
,
for
measuring
dimensions
with
great
accuracy
.
Micrometer head
the
head
of
a
micrometer
screw
.
Micrometer microscope
a
compound
microscope
combined
with
a
filar
micrometer
,
used
chiefly
for
reading
and
subdividing
the
divisions
of
large
astronomical
and
geodetical
instruments
.
Micrometer screw
a
screw
with
a
graduated
head
used
in
some
forms
of
micrometers
;
turning
the
head
one
full
revolution
advances
the
position
of
the
tip
of
the
screw
only
by
a
little
.
Position micrometer
See
under
Position
.
Scale micrometer
a
minute
and
very
delicately
graduated
scale
of
equal
parts
used
in
the
field
of
a
telescope
or
microscope
,
for
measuring
distances
by
direct
comparison
.
Related Words
metric
linear
unit
,
micromillimeter
,
micromillimetre
,
micron
,
millimeter
,
millimetre
,
millimicron
,
mm
,
nanometer
,
nanometre
,
nm
Search
Word:
Browse
Microcyte
Microdont
Microfarad
Microfilm
Microform
Micrograph
Micrographic
Micrography
Microhm
Microlepidoptera
Microlestes
Microlite
Microlith
Microlithic
Micrologic
Micrology
micromercurialism
Micromere
micrometeorite
micrometeoritic
Micrometer caliper
Micrometer head
Micrometer microscope
Micrometer screw
Micrometric
Micrometry
Micromillimeter
Micromyx
micron
Micronesian
Micronesians
Micronometer
Microorganism
Micropantograph
Microparasite
Micropegmatite
microphone
microphonic
microphonics
microphonous
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
© 2008
Interapple, Inc.
Cover
