diff --git a/docs/Makefile b/docs/Makefile
index ea283eb..26cb8ec 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -18,7 +18,7 @@ help:
 snippets:
 	@echo "Generating $@"
 	@symbiflow -h > help.txt
-	@for cmd in all syn imp bit pgm; do \
+	@for cmd in all syn pnr bit pgm; do \
 		symbiflow $$cmd -h > help-$$cmd.txt ; \
 	done
 	@echo "$@ generated"
diff --git a/docs/devices.py b/docs/devices.py
index c9b79c6..05b42d8 100644
--- a/docs/devices.py
+++ b/docs/devices.py
@@ -11,7 +11,7 @@ def gen_file(filename, default, families, packages):
                 part = "{}-{}".format(family, package)
                 obj.set_part(part)
                 try:
-                    obj.implementation()
+                    obj.pnr()
                     parts.append(part)
                 except:
                     print('Unsupported part {}'.format(part))
diff --git a/docs/user-guide.rst b/docs/user-guide.rst
index eda54e7..4f635f9 100644
--- a/docs/user-guide.rst
+++ b/docs/user-guide.rst
@@ -16,10 +16,10 @@ symbiflow syn
 
 .. literalinclude:: help-syn.txt
 
-symbiflow imp
+symbiflow pnr
 -------------
 
-.. literalinclude:: help-imp.txt
+.. literalinclude:: help-pnr.txt
 
 symbiflow bit
 -------------
diff --git a/examples/Makefile b/examples/Makefile
index 60d6d0e..4e2353f 100644
--- a/examples/Makefile
+++ b/examples/Makefile
@@ -10,7 +10,7 @@ VLOGDIR = ../resources/verilog
 CONSDIR = ../resources/constraints/$(BOARD)
 
 
-test: all syn imp bit
+test: all syn pnr bit
 
 #
 # Complete flow examples
@@ -21,7 +21,7 @@ all: all-ice40
 all-ice40:
 	symbiflow all --oci-engine $(ENGINE) --part $(ICE40) \
 		--vlog $(VLOGDIR)/blink.v \
-		--icf $(CONSDIR)/clk.pcf $(CONSDIR)/led.pcf \
+		--pcf $(CONSDIR)/clk.pcf $(CONSDIR)/led.pcf \
 		--top Blink -o build-ice40 --project ice40
 
 #
@@ -99,18 +99,18 @@ syn-ecp5:
 		--top Blink -o build-ecp5 --project ecp5
 
 #
-# Implementation examples
+# Place and Route examples
 #
 
-imp: imp-ice40 imp-ecp5
+pnr: pnr-ice40 pnr-ecp5
 
-imp-ice40:
-	symbiflow imp --oci-engine $(ENGINE) --part $(ICE40) \
-		--icf $(CONSDIR)/clk.pcf $(CONSDIR)/led.pcf \
+pnr-ice40:
+	symbiflow pnr --oci-engine $(ENGINE) --part $(ICE40) \
+		--pcf $(CONSDIR)/clk.pcf $(CONSDIR)/led.pcf \
 		-o build-ice40 --project ice40
 
-imp-ecp5:
-	symbiflow imp --oci-engine $(ENGINE) --part $(ECP5) \
+pnr-ecp5:
+	symbiflow pnr --oci-engine $(ENGINE) --part $(ECP5) \
 	-o build-ecp5 --project ecp5
 
 #
diff --git a/examples/README.md b/examples/README.md
index c54070c..ee3b163 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -18,7 +18,7 @@ bash icestick.sh program
 
 ```bash
 make syn-ice40
-make imp-ice40
+make pnr-ice40
 make bit-ice40
 make pgm-ice40
 ```
diff --git a/examples/icestick.sh b/examples/icestick.sh
index 7fc38a6..69a36e3 100644
--- a/examples/icestick.sh
+++ b/examples/icestick.sh
@@ -6,10 +6,10 @@ symbiflow syn --oci-engine docker --part hx1k-tq144 \
   --vlog ../resources/verilog/blink.v \
   --top Blink -o build-icestick --project icestick
 
-echo "Implementation"
+echo "Place and Route"
 
-symbiflow imp --oci-engine docker --part hx1k-tq144 \
-  --icf ../resources/constraints/icestick/clk.pcf ../resources/constraints/icestick/led.pcf \
+symbiflow pnr --oci-engine docker --part hx1k-tq144 \
+  --pcf ../resources/constraints/icestick/clk.pcf ../resources/constraints/icestick/led.pcf \
   -o build-icestick --project icestick
 
 echo "Bitstream generation"
@@ -28,7 +28,7 @@ echo "From Synthesis to Bitstream generation in one step (VHDL)"
 
 symbiflow all --oci-engine docker --part hx1k-tq144 \
   --vhdl ../resources/vhdl/blink.vhdl \
-  --icf ../resources/constraints/icestick/clk.pcf ../resources/constraints/icestick/led.pcf \
+  --pcf ../resources/constraints/icestick/clk.pcf ../resources/constraints/icestick/led.pcf \
   --top Blink -o build-icestick --project icestick
 
 if [ "$1" == "program" ]; then
diff --git a/symbiflow/cli.py b/symbiflow/cli.py
index 506fc8d..fa7ed5d 100644
--- a/symbiflow/cli.py
+++ b/symbiflow/cli.py
@@ -21,7 +21,7 @@
 
 _ALL_DESC = 'Performs from synthesis to bitstream generation'
 _SYN_DESC = 'Performs synthesis'
-_IMP_DESC = 'Performs implementation'
+_PNR_DESC = 'Performs place and route'
 _BIT_DESC = 'Performs bitstream generation'
 _PGM_DESC = 'Performs programming'
 
@@ -31,7 +31,7 @@
 _DEF_OCI_VOLUMES = ['$HOME:$HOME']
 _DEF_OCI_WORK = '$PWD'
 
-_COMMANDS = ['all', 'syn', 'imp', 'bit', 'pgm']
+_COMMANDS = ['all', 'syn', 'pnr', 'bit', 'pgm']
 
 
 # pylint: disable=too-many-statements
@@ -154,14 +154,14 @@ def main():
         help='Synthesis Constraint Files'
     )
 
-    # Arguments for implementation
+    # Arguments for pnr
 
-    args_for_imp = argparse.ArgumentParser(add_help=False)
-    args_for_imp.add_argument(
-        '--icf',
+    args_for_pnr = argparse.ArgumentParser(add_help=False)
+    args_for_pnr.add_argument(
+        '--pcf',
         metavar='FILE',
         nargs='+',
-        help='Implementation Constraint Files'
+        help='Physical Constraint Files'
     )
 
     #
@@ -188,7 +188,7 @@ def main():
         'all',
         description=_ALL_DESC,
         help=_ALL_DESC,
-        parents=[args_for_syn, args_for_imp, args_shared]
+        parents=[args_for_syn, args_for_pnr, args_shared]
     )
 
     subparsers.add_parser(
@@ -199,10 +199,10 @@ def main():
     )
 
     subparsers.add_parser(
-        'imp',
-        description=_IMP_DESC,
-        help=_IMP_DESC,
-        parents=[args_for_imp, args_shared]
+        'pnr',
+        description=_PNR_DESC,
+        help=_PNR_DESC,
+        parents=[args_for_pnr, args_shared]
     )
 
     subparsers.add_parser(
@@ -249,8 +249,8 @@ def main():
     if args.command in ['all', 'syn']:
         prj.synthesis(args.top, args.vhdl, args.vlog, args.slog, args.scf,
                       args.param, args.arch, args.define, args.include)
-    if args.command in ['all', 'imp']:
-        prj.implementation(args.icf)
+    if args.command in ['all', 'pnr']:
+        prj.pnr(args.pcf)
     if args.command in ['all', 'bit']:
         prj.bitstream()
     if args.command == 'pgm':
diff --git a/symbiflow/symbiflow.py b/symbiflow/symbiflow.py
index 4fc6c55..70f753e 100644
--- a/symbiflow/symbiflow.py
+++ b/symbiflow/symbiflow.py
@@ -162,18 +162,18 @@ def _vhdl_options(self, arch, param):
         )]
         return options
 
-    def implementation(self, icf=None):
-        """Performs implementation.
+    def pnr(self, pcf=None):
+        """Performs Place and Route.
 
-        :param icf: Implementation Constraint Files
-        :type icf: list
+        :param pcf: Physical Constraint Files
+        :type pcf: list
         """
         family = self.part['family']
         if family == 'ice40':
             ext = 'pcf'
         else:  # family == 'ecp5'
             ext = 'lpf'
-        self._create_constraint(icf, ext)
+        self._create_constraint(pcf, ext)
         # Prepare and run P&R
         cmd = _template('nextpnr-{}'.format(family)).format(
             command=self.oci.get_command('nextpnr-{}'.format(family)),