Are all bugs considered insects

Yes, taxonomically speaking, all bugs are considered insects even though no, practically speaking, they are not. A bug formally, puristically, technically speaking is supposed to be a member of the insect order Hemiptera. But in actual practice, its use will be found expanded to include the arachnid (mite, scorpion, spider, tick), insect, myriapod (centipede, millipede), terrestrial crab, and woodlouse representatives -- but not aquatic crustaceans or horseshoe crabs -- of the invertebrate phylum Arthropoda of jointed appendage- and segmented body-bearers.