Really, basic research is not that difficult. All you have to do is look at Wikipedia. If you don't believe them then follow the footnotes to the sources.
quote:Herbert Spencer first used the phrase — after reading Charles Darwin's On the Origin of Species — in his Principles of Biology (1864), in which he drew parallels between his own economic theories and Darwin's biological ones, writing, "This survival of the fittest, which I have here sought to express in mechanical terms, is that which Mr. Darwin has called 'natural selection', or the preservation of favoured races in the struggle for life."[1]
Darwin first used Spencer's new phrase "survival of the fittest" as a synonym for natural selection in the fifth edition of On the Origin of Species, published in 1869.[2][3] Darwin meant it as a metaphor for "better adapted for immediate, local environment", not the common inference of "in the best physical shape".[4] Hence, it is not a scientific description