Interchromosomic vs Intrachromosomic Recombinations
The prefix inter- means "between two or more", and the prefix intra- means "within one".

So interchromosomal recombination means recombination between two different chromosomes (for example, it normally and often occurs between each homologous paternal and maternal chromosome pair during the Prophase I stage of meiosis).

Intrachromosomal recombination would mean recombination within a single chromosome.