When it comes to expressing something in a brief yet powerful manner, "in a word" is a phrase that comes in handy. However, if you're looking to add a bit of variety to your language, it's always useful to have some synonyms on hand. Consider using phrases such as "in short," "briefly stated," "to sum up," "in essence," or "in summary." These options allow you to convey the same idea with slightly different nuances depending on the situation in which they're used. Whether you're writing a report, giving a presentation, or having a conversation with someone, having a range of vocabulary options will always serve you well.