A toe was a digit found on the foot of an animal. Toes were typically covered with protective toenails, which on certain animals formed a hoof. (TNG: "Suddenly Human") Toes were especially susceptible to minor injuries, such as being stubbed. (TNG: "Deja Q"; VOY: "Tuvix", "Extreme Risk")
During a transporter-induced hallucination in 2152, Hoshi Sato regarding the experience she thought she had as being "very unsettling", inquiring to Trip Tucker if he felt the same way. He concurred, that it did "[f]or a minute or two, but once I counted my fingers and toes." (ENT: "Vanishing Point")
Sometime prior to 2152, the alien Zoumas was stranded for three months on the polar islands of Burala Prime. One day he became lost, outside of the local outpost, for fourteen hours; as a result, he lost three toes to frostbite. As such, he had walked with a slight limp ever since. He intended to return to the planet one day to get a certain surgeon there "do some work" on my foot, and maybe replace the missing toes. (ENT: "Canamar")
While James T. Kirk speculated the possibility that Charlie Evans may not be an Earthling, and may actually be Thasian in 2266, Doctor Leonard McCoy disputed Kirk, stating, "No, I don't think so, not unless they're exactly like Earthlings. The development of his fingers and toes exactly matches the present development of Mans on Earth." (TOS: "Charlie X")
When Kirk, McCoy, and Spock later visited Nazi-controlled Ekos undercover in 2267, the right boot McCoy was issued was too tight. The situation was remedied by Spock, who explained that "[t]here is a logical way to proceed, Doctor. Point your toe, apply equal pressure to either side of the boot, and push." (TOS: "Patterns of Force")
Ocampans were generally born toes first. In an alternate 2374, when Kes gave birth aboard a Class 2 shuttlecraft to her and Tom Paris' daughter, Linnis, Paris' first reaction to the birth was "I can see the toes, it's coming." Prior to this, during the birth of Kes, herself, her father, Benaren, also first exclaimed "I can see the toes!" upon her arrival. (VOY: "Before and After")
During a rings contest between Kathryn Janeway and Michael Sullivan in 2376, Janeway complained that Sullivan cheated because he "stepped over the beer stain [..] by half a boot, and then [..] moved back, hoping I wouldn't notice." Sullivan explained that that was not true, because "[t]hese boots are half a size too large, so in reality my toes never crossed the line." (VOY: "Fair Haven")