beryllium
beryllium — noun
1. a silver-grey metallic chemical element (symbol Be) that is very light and stron
a silver-grey metallic chemical element (symbol Be) that is very light and strong. It is mixed with other metals to make them harder, but its dust is poisonous if breathed in.
Beryllium is lighter than steel yet very strong, and is used in aircraft parts.
uncountable noun — element name, no article
The Watanabe laboratory developed a new beryllium-copper alloy for deep-sea drilling equipment.
compound modifier: beryllium-copper
Workers who handle beryllium must wear masks because the fine dust damages their lungs.
Beryllium occurs naturally in gemstones such as emeralds and aquamarines.
Because beryllium lets X-rays pass through it, the metal is used in medical imaging machines.
用法筆記
Beryllium is an uncountable (mass) noun — you cannot say 'a beryllium' or 'berylliums'. It is referred to with the singular pronoun 'it'.