What does protoplasm mean?
Protoplasm is the living material within a cell, encompassing the cytoplasm and its internal structures while excluding the nucleus. Historically, before modern cell biology developed a detailed vocabulary for organelles and membranes, the word was widely used to describe the substance that made cells alive. It occurs in discussions of cell physiology, microscopy, plant and animal biology, and the physical or chemical changes associated with living material. Although “cytoplasm” is often more precise in contemporary scientific writing, “protoplasm” remains useful when emphasizing the living character of a cell's internal material. The word is also familiar from older scientific literature, in which cellular activity was frequently described as changes in the condition or composition of the protoplasm.
nounThe living contents of a cell, including the cytoplasm and its structures, but excluding the nucleus. In modern biology, the term is mainly used when discussing the physical and chemical nature of living cell material.
- The living contents of a cell, including the cytoplasm and organelles but excluding the nucleus.
"The cell membrane regulates the movement of substances into and out of the protoplasm."
"Microscopic changes in the protoplasm revealed that the cells were still alive."
"The membrane separates the internal protoplasm from the surrounding environment."
The plural is grammatically possible but uncommon; discussions of cell material usually use the mass noun “protoplasm.”
"The slide contained several protoplasms from damaged cells."
Before cells were understood as complex microscopic worlds, “protoplasm” was a vivid name for the living stuff that filled them.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does protoplasm come from?
The word comes from Greek protos, meaning “first,” and plasma, meaning “something molded” or “formative material,” ultimately associated with the verb plassein, “to mold.” The term was adopted in 19th-century biology for the substance of living cells and later developed into related forms such as protoplasmic and protoplasmal.
Related word forms
How protoplasm is actually used
The term is now less common in precise modern cellular biology than “cytoplasm,” but it remains standard in biological discussion, microscopy, and historical descriptions of living matter. It is generally not used for the nucleus.
Easily confused with protoplasm
Cytoplasm is the material within a cell outside the nucleus, whereas protoplasm traditionally denotes the cell's living contents more broadly and is often used in a biological or historical sense.