Pierre and Marie Curie are best known for their pioneering work in the study of radioactivity, which led to their discovery in 1898 of the elements radium and polonium.
1 The beam of your boat is the width at the widest part of the boat.  To measure the beam, stand inside the boat and run a measuring tape from the port (left) side to the starboard (right) side at the widest section of your boat.
Noun. 1. girder-a beam made usually of steel; a main support in a structure. beam-long thick piece of wood or metal or concrete, etc., used in construction. I-beam-girder having a cross section resembling the letter `I'.irder. n. 1. (Building) a large beam, esp one made of steel, used in the construction of bridges, buildings, etc. 2. (Botany) botany the structure composed of tissue providing mechanical support for a stem or leaf.