T0 or T00 may refer to: * T0 space, a Kolmogorov space * HMNZS Wakakura (T00), a First World War Royal New Zealand Navy Castle class naval trawler * Same-day affirmation of a trade in finance and also : * a non-small cell lung carcinoma staging code for no evidence of primary tumor * T00 : Chambers County Airport FAA LID * a level on the tornado TORRO scale