What does spectrogram mean?
A spectrogram is a graph that makes the frequency structure of a signal visible, most often by plotting frequency against time. The strength of each frequency component is typically represented through differences in brightness or color, allowing patterns that cannot easily be heard or recognized in the original recording to be identified. Speech analysts, musicians, wildlife researchers, and engineers use spectrograms to examine pronunciation, musical notes, animal calls, mechanical faults, and other acoustic features. The word combines spectrum, referring to a range of frequencies or wavelengths, with the suffix -gram, meaning a written or recorded representation. Although “spectrogram” can describe similar displays for non-audio signals, it most commonly refers to a visualization of sound over time.
nounA graph or image that represents the frequency components of a signal, usually showing frequency along one axis and time along the other, with the strength of each component indicated by shading or color. It is commonly used to analyze and display sound.
- A visual representation of the frequency content of a signal as it changes over time, commonly produced for sound.
- A related graphical display showing the distribution and strength of frequencies in a signal or other time-varying phenomenon.
"The spectrogram revealed a sudden drop in frequency as the aircraft passed overhead."
"Researchers examined the spectrogram to identify the bird calls hidden in the recording."
"The speech-recognition system compares incoming sounds with stored spectrogram patterns."
The plural is formed by adding -s.
"The laboratory compared spectrograms recorded under several different conditions."
A spectrogram turns sound into a visual map, making hidden patterns in speech, music, and machinery visible.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does spectrogram come from?
Spectrogram was formed within the scientific vocabulary of spectrum and related forms such as spectrometer and spectroscopy. It combines spectrum with the suffix -gram, from Greek gramma, meaning “written” or “letter,” and thus denotes a representation of a spectrum. The term developed as spectrography and spectrographic analysis were applied to the visual recording of sound frequencies.
Related word forms
How spectrogram is actually used
The term is primarily technical, but it is also used in linguistics, music analysis, medicine, and signal processing. In general use, it most often refers specifically to a time-frequency display of sound.
Easily confused with spectrogram
A spectroscope directly displays the wavelengths or frequencies present in light, whereas a spectrogram usually records and displays how signal frequencies vary over time.
A spectrum shows the distribution of frequencies or wavelengths in a signal or light, while a spectrogram represents that distribution over time, often as an image.