ɐ stˈiːm ɹˈɑːkɪt ˈɔːlsoʊ nˈoʊn æz ɐ hˈɑːt wˈɔːɾɚ ɹˈɑːkɪt ɪz ɐ θˈɜːməl ɹˈɑːkɪt ðæt jˈuːzᵻz wˈɔːɾɚ hˈɛld ɪn ɐ pɹˈɛʃɚ vˈɛsəl æɾə hˈaɪ tˈɛmpɹɪtʃɚ, sˈʌtʃ ðæt ɪts sˈætʃɚɹˌeɪɾᵻd vˈeɪpɚ pɹˈɛʃɚɹ ɪz sɪɡnˈɪfɪkəntli ɡɹˈeɪɾɚ ðɐn ˈæmbiənt pɹˈɛʃɚ.
A steam rocket (also known as a hot water rocket) is a thermal rocket that uses water held in a pressure vessel at a high temperature, such that its saturated vapor pressure is significantly greater than ambient pressure.