Pressure unit and Standard pressure

Pressure unit noun - A unit measuring force per unit area.

Standard pressure and pressure unit are semantically related. In some cases you can replace phrase "Standard pressure" with "Pressure unit", this phrases are similar.

Standard pressure noun - A unit of pressure: the pressure that will support a column of mercury 760 mm high at sea level and 0 degrees centigrade.

Pressure unit and standard pressure are semantically related. You can use "Pressure unit" instead a noun phrase "Standard pressure".