Is it 'duct' or 'duck' tape?

For temporary floor marking, removes cleanly up to 3 weeks. Not for hardwood or direct sunlight. Heavy duty- excellent for repairs, crafting

Duck Brand Duck Color Duct Tape, 6-Roll, Baby Pink (240976_C)

Duck Brand Fun Duct Tape Chrome 1.88 X 10 280621 : Target

Duck® Brand Color Duct Tape - Aqua, 1.88 Inch x 20 Yard - Fred Meyer

How Duck Tape Became Famous

Duck Brand Digital Camouflage Printed Duct Tape

Duck Tape® Brand All Purpose Duct Tape

Beige Tan Duck brand Duct Tape 1.88 inch x 20 yds

Color Duck Tape® Brand Duct Tape - Gold, 1.88 in. x 15 yd.

SHURTAPE DUCK TAPE 6 Rolls of Silver Duct Tape 1.88 X 20 YD 281932

Duck Tape® Solid Color Duct Tape

The Original Strength Duck Tape® Brand Duct Tape- Black, 1.88 in. x 55 yd.