sheepdog
US /ˈʃiːp.dɑːɡ/
UK /ˈʃiːp.dɑːɡ/

1.
a dog of a breed trained to herd sheep
:
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The clever sheepdog quickly gathered the scattered flock.
•
Many breeds of sheepdog are known for their intelligence and loyalty.
a dog of a breed trained to herd sheep