The definition of entomology says it is the science of studying insects.

I know spiders are not insects but does entomology include studying spiders as well?

Otherwise is there any name to the science of studying spiders (class Arachnida)?


3 Answers 3


Spiders are part of a taxon called Arachnida. Arachnida also contain scorpions, Oppiliones, acari, … The science of arachnids is logically called Arachnology

However, (wikipedia):

Entomology (from Greek ἔντομος, entomos, "that which is cut in pieces or engraved/segmented", hence "insect"; and -λογία, -logia) is the scientific study of insects, a branch of arthropodology. In the past the term "insect" was more vague, and historically the definition of entomology included the study of terrestrial animals in other arthropod groups or other phyla, such as arachnids, myriapods, earthworms, land snails, and slugs. This wider meaning may still be encountered in informal use.

In other words, in the informal sense entomology include arachnology but the strict definition entomology does not encompass arachnology.

You will find here on tolweb.org more information about the systematics of Arthropoda

  • $\begingroup$ I understand this. But generally the term Arachnology seems not very used; even the wikipedia's article seems incomplete or needs more "inline citations". In the other side, it was looking entomology includes spiders and some other non-insect animals in the past but it is not clear if it is still accepted or if any other animals should go in thier specific terms. $\endgroup$
    – рüффп
    May 30, 2014 at 18:42
  • $\begingroup$ @ruffp I am not sure I understand your comment.. You know, all this is just a matter of definitions. And the definition of entomology has not real importance to science, just like the definition of biology itself is not of real important to biologists. So, what has to be known is that some people use "entomology" this way and some people use "entomology" that way. And yes, of course this kind of definitions are changing over time. It is indeed likely that entomology has evolved to be used in a more and more restrictive way as everybody accepted that spiders are not insects for quite a while. $\endgroup$
    – Remi.b
    May 30, 2014 at 18:53
  • $\begingroup$ I had this question when I start to use this site to ask questions about spiders and I did not know if I can tag them with Entomology because there is no Arachnology tag. I did not know as well if this question can be in the meta site or here, but because I wanted a general answer not specifically related with tagging on this site, I post it here. $\endgroup$
    – рüффп
    May 31, 2014 at 15:31

As a general rule no. Spiders and other arachnids generally tend to have their own field of study called arachnology.


The term entomology is derived from the Greek words Entomo ("Insect") and Logia(word) . Considering that Entomo generally refers to insect(s) the question is whether Arachnids could be considered entoma in Greek as there is no other used term that refers to arachnids.

  • 2
    $\begingroup$ Although this answer gets at the etymology of entomology, it doesn't quite consider the usage which seems to be more important here, and doesn't have any citation for that usage. There are lots of words for which the etymology is not particularly instructive for the usage since usages change. $\endgroup$
    – Bryan Krause
    Jul 22, 2019 at 20:48

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