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WXY&Z

Below is a collection of commonly used science vocabulary words. If you don’t see a word you are looking for, try visiting Merriam-Webster’s Learner’s Dictionary (a dictionary for younger science students) or other recommended online dictionaries.

W

Water

a clear liquid that has no color, taste, or smell, that falls from clouds as rain, that forms streams, lakes, and seas, and that is used for drinking, washing, etc. It has the molecular formula H2O.

Weathering

a physical, chemical, and/or biological process that breaks up all rock types (sedimentary, igneous, or metamorphic) into smaller pieces called sediments.

Wetland

A wetland can be a hard term to define.  In the most general terms, wetlands are lands on which water covers the soil or is present either at or near the surface of the soil (or within the root zone) all year long OR for varying periods of time during the year.  Wetlands can most reliably be identified by the presence of certain types of plants (called hydrophytes) that are adapted to life in certain types of soils (called hydric soils) that form under flooded or saturated conditions. Thus, a patch of land that develops pools of water after a rain storm would typically not be considered a wetland, even though the land is wet.

Wet mass

mass of an object–or sample of an object–before it is completely dry. In other words, it is the mass of the object prior to the entire concentration of water having been effectively removed from it. Wet mass is sometimes known as wet weight, wet matter, and/or fresh mass.

  • Compared to the measurement known as dry mass–which excludes the mass of the water–wet mass is typically more unreliable for comparisons because the concentration of water inside of living tissue can vary/change so much.

X

X-Axis (in mathematics)

horizontal line at the bottom of a graph, which can be labeled to give information about what the graph represents.

Xylem tissue (also Xylem tubes)

xylem tissue, or sometimes just xylem, is the specialized tissue of vascular plants that transports water and nutrients from the roots up to the stems and leaves. Xylem tissue also often provides structural support for the plant, as well as a place for storage. When xylem tissue is arranged to form hollow tubes these structures are called xylem tubes.

Y

Y-Axis (in mathematics)

vertical line to the left or right of a graph, which can be labeled to give information about what the graph represents.

Z

Zygote

a single cell produced by the union of the male (sperm) and female (egg) gametes. 

Last updated: September 2022